Flame-Resistant Hybrid Inorganic-Polymeric Solid-State Electrolytes and Lithium Batteries Containing Same

ABSTRACT

A rechargeable lithium battery comprising an anode, a cathode, and a hybrid electrolyte in ionic communication with the anode and the cathode, wherein: (a) the hybrid electrolyte comprises a mixture of a polymer and particles of an inorganic solid electrolyte; (b) the polymer is a polymerization or crosslinking product of a reactive additive, wherein the reactive additive comprises (i) a first liquid solvent that is polymerizable, (ii) an initiator or curing agent, and (iii) a lithium salt; (c) the polymer is present in the anode, the cathode, the separator, between the anode and the separator, or between the cathode and the separator; and (d) the hybrid electrolyte forms a contiguous phase in the cathode or in the anode, and occupies from 3% to 40% by volume of the cathode or from 3% to 40% by volume of the anode. Also provided is a process for producing the lithium cell.

FIELD

The present disclosure provides a fire/flame-resistant electrolyte andlithium batteries (lithium-ion and lithium metal batteries) containingsuch an electrolyte. The polymeric portion of the hybrid electrolyte ispreferably cured or solidified in situ inside an electrode, a separator,and/or a battery cell.

BACKGROUND

Rechargeable lithium-ion (Li-ion) and lithium metal batteries (e.g.,lithium-sulfur, lithium selenium, and Li metal-air batteries) areconsidered promising power sources for electric vehicle (EV), hybridelectric vehicle (HEV), and portable electronic devices, such as lap-topcomputers and mobile phones. Lithium as a metal element has the highestlithium storage capacity (3,861 mAh/g) compared to any other metal ormetal-intercalated compound as an anode active material (exceptLi_(4.4)Si, which has a specific capacity of 4,200 mAh/g). Hence, ingeneral, Li metal batteries (having a lithium metal anode) have asignificantly higher energy density than lithium-ion batteries (having agraphite anode).

However, the liquid electrolytes used for lithium-ion batteries and alllithium metal secondary batteries pose some safety concerns. Most of theorganic liquid electrolytes can cause thermal runaway or explosionproblems.

Ionic liquids (ILs) are a new class of purely ionic, salt-like materialsthat are liquid at unusually low temperatures. The official definitionof ILs uses the boiling point of water as a point of reference: “Ionicliquids are ionic compounds which are liquid below 100° C.”. Aparticularly useful and scientifically interesting class of ILs is theroom temperature ionic liquid (RTIL), which refers to the salts that areliquid at room temperature or below. RTILs are also referred to asorganic liquid salts or organic molten salts. An accepted definition ofan RTIL is any salt that has a melting temperature lower than ambienttemperature.

Although ILs were suggested as a potential electrolyte for rechargeablelithium batteries due to their non-flammability, conventional ionicliquid compositions have not exhibited satisfactory performance whenused as an electrolyte likely due to several inherent drawbacks: (a) ILshave relatively high viscosity at room or lower temperatures; thus beingconsidered as not amenable to fast lithium ion transport; (b) For Li—Scell uses, ILs are capable of dissolving lithium polysulfides at thecathode and allowing the dissolved species to migrate to the anode(i.e., the shuttle effect remains severe); and (c) For lithium metalsecondary cells, most of the ILs strongly react with lithium metal atthe anode, continuing to consume Li and deplete the electrolyte itselfduring repeated charges and discharges. These factors lead to relativelypoor specific capacity (particularly under high current or highcharge/discharge rate conditions, hence lower power density), lowspecific energy density, rapid capacity decay and poor cycle life.Furthermore, ILs remain extremely expensive. Consequently, as of today,no commercially available lithium battery makes use of an ionic liquidas the primary electrolyte component.

Solid state electrolytes are commonly believed to be safe in terms offire and explosion proof. Solid state electrolytes can be divided intoorganic (polymeric), inorganic, organic-inorganic compositeelectrolytes. However, the conductivity of well-known organic polymersolid state electrolytes, such as poly(ethylene oxide) (PEO),polypropylene oxide (PPO), poly(ethylene glycol) (PEG), andpoly(acrylonitrile) (PAN), is typically low (<10⁻⁵ S/cm).

Although the inorganic solid-state electrolyte (e.g., garnet-type andmetal sulfide-type) can exhibit a high conductivity (from 0.05×10⁻³ to10⁻² S/cm), the interfacial impedance or resistance between theinorganic solid-state electrolyte and the electrode (cathode or anode)is high. Further, the traditional inorganic ceramic electrolyte is verybrittle and has poor film-forming ability and poor mechanicalproperties. These materials cannot be cost-effectively manufactured.

Furthermore, the most serious drawback of implementing the inorganicsolid electrolyte (ISE) in an electrode (anode or cathode) is the notionthat it would normally take a high loading of the ISE particles(typically 30-60% by volume) to meet the two essential conditions: (i)the electrolyte must form a contiguous phase through which lithium ionscan travel to reach individual particles of an electrode (anode orcathode) active material; and (ii) substantially each and everyelectrode active material particle (e.g., graphite or Si particles inthe anode or lithium metal oxide particles in the cathode) must be inphysical contact with this contiguous electrolyte phase. This impliesthat the proportion of the electrode active material responsible for thelithium ion storage capability in an electrode would be reduced to lessthan 40-70%, leading to a significantly reduced energy density of theresulting battery cell. It is thus essential to minimize the amounts ofthe electrolyte and other non-active materials, such as conductivefiller and binder, in an electrode.

The applicant's research group has previously developed the quasi-solidelectrolytes (QSE), which may be considered as a fourth type ofsolid-state electrolyte. In certain variants of the quasi-solidelectrolytes, a small amount of liquid electrolyte may be present tohelp improving the physical and ionic contact between the electrolyteand the electrode, thus reducing the interfacial resistance. A smallproportion of liquid solvent dispersed in a majority of polymer matrixmay be referred to as a state of “solvent-in-polymer”. If the liquidsolvent forms a continuous phase we have a state of“polymer-in-solvent”. Both are herein referred to as a quasi-solidelectrolytes. Examples of QSEs are disclosed in the following: Hui He,et al. “Lithium Secondary Batteries Containing a Non-flammableQuasi-solid Electrolyte,” U.S. patent application Ser. No. 13/986,814(Jun. 10, 2013); U.S. Pat. No. 9,368,831 (Jun. 14, 2016); U.S. Pat. No.9,601,803 (Mar. 21, 2017); U.S. Pat. No. 9,601,805 (Mar. 21, 2017); U.S.Pat. No. 9,059,481 (Jun. 16, 2015).

However, the presence of certain liquid electrolytes may cause someproblems, such as liquid leakage, gassing, and low resistance to hightemperature. Therefore, a novel electrolyte system that obviates all ormost of these issues is needed.

Hence, a general object of the present disclosure is to provide a safe,flame/fire-resistant, quasi-solid or solid-state electrolyte system fora rechargeable lithium cell that is compatible with existing batteryproduction facilities. It is a further object of the present disclosureto provide an electrolyte that occupies a minimal proportion of thetotal volume of an electrode, yet still forms a contiguous phase in theelectrode and is in physical contact with substantially all theelectrode active material particles.

SUMMARY

The present disclosure provides rechargeable lithium battery cellcomprising an anode, a cathode, and a hybrid quasi-solid or solid-stateelectrolyte in ionic communication with the anode and the cathode,wherein: (a) the hybrid electrolyte comprises a mixture of a polymer andan inorganic solid electrolyte (ISE); (b) the polymer is apolymerization or crosslinking product of a reactive additive, whereinthe reactive additive comprises (i) a first liquid solvent that ispolymerizable, (ii) an initiator or curing agent, and (iii) a lithiumsalt; wherein the first liquid solvent occupies from 1% to 99% by weightbased on the total weight of the reactive additive; (c) the polymer ispresent in the anode, the cathode, the separator, an interface betweenthe anode and the separator, or an interface between the cathode and theseparator; and (d) the hybrid electrolyte forms a contiguous phase inthe cathode and/or in the anode, and occupies from 3% to 40% (preferablyless than 30%, more preferably less than 25%, further preferably lessthan 20%, even more preferably less than 15%, and most preferably lessthan 10%) by volume of the cathode and/or from 3% to 40% (preferablyless than 30%, more preferably less than 25%, further preferably lessthan 20%, even more preferably less than 15%, and most preferably lessthan 10%) by volume of the anode.

Preferably, the hybrid electrolyte (particles of the inorganic solidelectrolyte, ISE, and the polymer mixed together) has a lithium ionconductivity from 10⁻⁵ S/cm to 5×10⁻² S/cm. Preferably, the polymeralone (without the ISE) has a lithium ion conductivity from 10⁻⁸ S/cm to5×10⁻² S/cm, more typically from 10⁻⁶ S/cm to 10⁻² S/cm, more preferablygreater than 10⁻⁵ S/cm, further more preferably greater than 10⁻⁴ S/cm,and most preferably greater than 10⁻³ S/cm.

In certain embodiments, the inorganic solid electrolyte material ispresent in the form of discrete particles (preferably from 10 nm to 5 μmin diameter) which are dispersed in or bonded by a polymer electrolyte(quasi-solid or solid-state polymer). The solid electrolyte materialparticles and the polymer electrolyte are adjacent to and physicallyconnected to one another to form contiguous pathways for lithium ions.

In certain embodiments, the inorganic solid electrolyte material isselected from an oxide type, sulfide type, hydride type, halide type,borate type, phosphate type, lithium phosphorus oxynitride (LiPON),garnet-type, lithium superionic conductor (LISICON) type, sodiumsuperionic conductor (NASICON) type, or a combination thereof.

Preferably, at least 20% by weight of the polymerizable first liquidsolvent is polymerized; more preferably >50%, further preferably >70%,and most preferably >99% is polymerized.

In certain embodiments, the first liquid solvent comprises a liquidselected from the group consisting of vinylene carbonate, ethylenecarbonate, fluoroethylene carbonate, ethylene glycol phenyl etheracrylate) (PEGPEA), ethoxylated trimethyl propyl triacrylate (ETPTA),tetrahydrofuran (THF), vinyl sulfite, vinyl ethylene sulfite, vinylethylene carbonate, 1,3-propyl sultone, 1,3,5-trioxane (TXE),1,3-acrylic-sultones, methyl ethylene sulfone, methyl vinyl sulfone,ethyl vinyl sulfone, methyl methacrylate, vinyl acetate, acrylamide,1,3-dioxolane (DOL), fluorinated ethers, fluorinated esters, sulfones,sulfides, dinitriles, acrylonitrile (AN), sulfates, siloxanes, silanes,N-methylacetamide, acrylates, ethylene glycols, phosphates,phosphonates, phosphinates, phosphines, phosphine oxides, phosphonicacids, phosphorous acid, phosphites, phosphoric acids, phosphazenecompounds, derivatives thereof, and combinations thereof.

In the conventional lithium-ion battery or lithium metal batteryindustry, the organic liquid solvents listed above are commonly used asa solvent to dissolve a lithium salt therein and the resulting solutionsare used as a liquid electrolyte. These liquid solvents are capable ofdissolving a high amount of a lithium salt; however, many of them arehighly volatile, having a low flash point and being highly flammable.Further, these liquid solvents are generally not known to bepolymerizable, with or without the presence of a second liquid solvent,and a separate or different polymer or monomer is typically used in theindustry to prepare a gel polymer electrolyte or solid polymerelectrolyte.

It is uniquely advantageous to be able to polymerize the liquid solventonce the liquid electrolyte (having a lithium salt dissolved in thefirst liquid solvent) is injected into an electrode or into a batterycell. With such a novel strategy, one can readily reduce the volatileliquid solvent or completely eliminate the volatile liquid solvent alltogether. A desired amount of a second liquid solvent, preferably aflame-resistant liquid solvent, such as an ionic liquid, may be retainedin the battery cell to improve the lithium ion conductivity of theelectrolyte. This strategy enables us to achieve several desirableattributes of the resultant electrolyte: no liquid electrolyte leakageissue (the in situ cured polymer being capable of holding the remainingliquid together to form a gel or a “solvent-in-polymer” phase), adequatelithium salt amount, good lithium ion conductivity, reduced oreliminated flammability, good ability of the electrolyte to wet thesurfaces of anode/cathode active materials (hence, significantly reducedinterfacial impedance and internal resistance), processing ease,compatibility with current lithium-ion battery production processes andequipment, etc. This is of significant utility value since most of theorganic solvents commonly used in the lithium battery are known to bevolatile and flammable, posing a fire and explosion danger. Further,current solid-state electrolytes are not compatible with existinglithium-ion battery manufacturing equipment and processes.

The first polymerizable liquid solvent or the second liquid solvent maycomprise an ionic liquid. The ionic liquid may be selected from thegroup consisting of room temperature ionic liquids having a cationselected from tetraalkylammonium, di-, tri-, or tetra-alkylimidazolium,alkylpyridinium, dialkyl-pyrrolidinium, dialkylpiperidinium,tetraalkylphosphonium, hexakis(bromomethyl)benzene, andtrialkylsulfonium, 1-vinyl-3-dodecyl imidazoliumbis(trifluoromethanesulfonyl) imide (VDIM-TFSI) or1-vinyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide(VMIMTFSI), 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (EMITFSI), [(poly(diallyldimethyl ammoniumbis(fluorosulfonyl)imide, (C₁₀H₁₆F₂N₂O₄S₂)n, vinylimidazolium monomerswith N-alkyl substituents, and combinations thereof.

In certain embodiments, the ionic liquid has an anion selected from BF₄⁻, B(CN)₄ ⁻, CH₃BF₃ ⁻, CH₂CHBF₃ ⁻, CF₃BF₃ ⁻, C₂F₅BF₃ ⁻, n-C₃F₇BF₃ ⁻,n-C₄F₉BF₃ ⁻, PF₆ ⁻, CF₃CO₂ ⁻, CF₃SO₃ ⁻, N(SO₂CF₃)₂ ⁻, N(COCF₃)(SO₂CF₃)⁻,N(SO₂F)₂ ⁻, N(CN)₂ ⁻, C(CN)₃ ⁻, SCN⁻, SeCN⁻, CuCl₂ ⁻, AlCl₄ ⁻,F(HF)_(2.3) ⁻, or a combination thereof.

In certain preferred embodiments, the second liquid solvent furthercomprises a flame retardant selected from an organic phosphoruscompound, an inorganic phosphorus compound, a halogenated derivativethereof, or a combination thereof. The organic phosphorus compound orthe inorganic phosphorus compound preferably is selected from the groupconsisting of phosphates, phosphonates, phosphonic acids, phosphorousacids, phosphites, phosphoric acids, phosphinates, phosphines, phosphineoxides, phosphazene compounds, derivatives thereof, and combinationsthereof. These liquid solvents, if polymerizable, may also serve as arust liquid solvent.

In certain embodiments, the first or the second liquid solvent comprisesa liquid solvent selected from the group consisting of fluorinatedethers, fluorinated esters, sulfones, sulfides, nitriles, sulfates,siloxanes, silanes, combinations thereof, and combinations withphosphates, phosphonates, phosphinates, phosphines, phosphine oxides,phosphonic acids, phosphorous acid, phosphites, phosphoric acids,phosphazene compounds, derivatives thereof, and combinations thereof.

In some embodiments, the first or the second liquid solvent is selectedfrom a phosphate, phosphonate, phosphinate, phosphine, or phosphineoxide having the structure of:

wherein R¹⁰, R¹¹, and R¹², are independently selected from the groupconsisting of alkyl, aryl, heteroalkyl, heteroaryl, halogen substitutedalkyl, halogen substituted aryl, halogen substituted heteroalkyl,halogen substituted heteroaryl, alkoxy, aryloxy, heteroalkoxy,heteroaryloxy, halogen substituted alkoxy, halogen substituted aryloxy,halogen substituted heteroalkoxy, and halogen substituted heteroaryloxyfunctional groups, and the second liquid solvent is stable under anapplied electrical potential no less than 4 V (preferably no less than4.5 V).

In some embodiments, the first or the second liquid solvent comprises aphosphoranamine having the structure of:

wherein R¹, R², and R³ are independently selected from the groupconsisting of alkyl, aryl, heteroalkyl, heteroaryl, halogen substitutedalkyl, halogen substituted aryl, halogen substituted heteroalkyl,halogen substituted heteroaryl, alkoxy, aryloxy, heteroalkoxy,heteroaryloxy, halogen substituted alkoxy, halogen substituted aryloxy,halogen substituted heteroalkoxy, and halogen substituted heteroaryloxyfunctional groups, wherein R¹, R², and R³ are represented by at leasttwo different substituents and wherein X is selected from the groupconsisting of an organosiylyl group or a tert-butyl group. The R¹, R²,and R³ may be each independently selected from the group consisting ofan alkoxy group, and an aryloxy group.

Preferably, the lithium salt occupies 0.1%-50% by weight and thecrosslinking agent and/or initiator occupies 0.1-50% by weight of thereactive additive.

In some embodiments, the polymer electrolyte exhibits a vapor pressureless than 0.001 kPa when measured at 20° C., a vapor pressure less than10% of the vapor pressure of the combined first liquid solvent andlithium salt alone without the polymerization, a flash point at least100 degrees Celsius higher than a flash point of the liquid solventalone, a flash point higher than 200° C., or no measurable flash pointand wherein the polymer has a lithium ion conductivity from 10⁻⁸ S/cm to10⁻² S/cm at room temperature.

In certain embodiments, the reactive additive (reactive liquidelectrolyte composition) comprises a polymerizable first liquid solventand an optional second liquid solvent (e.g., an ionic liquid) andwherein the second liquid solvent either is not polymerizable or ispolymerizable but polymerized to a lesser extent as compared to thefirst liquid solvent. The presence of this second liquid solvent isdesigned to impart certain desired properties to the polymerizedelectrolyte, such as improved lithium ion conductivity, flameretardancy, and the ability of the electrolyte to permeate into theelectrode (anode and/or cathode) to properly wet the surfaces of theanode active material and/or the cathode active material.

The second liquid solvent may further comprise an organic liquidselected from a fluorinated carbonate, hydrofluoroether, fluorinatedester, sulfone, nitrile, phosphate, phosphite, alkyl phosphonate,phosphazene, sulfate, siloxane, silane, 1,3-dioxolane (DOL),1,2-dimethoxyethane (DME), tetraethylene glycol dimethylether (TEGDME),poly(ethylene glycol) dimethyl ether (PEGDME), diethylene glycol dibutylether (DEGDBE), 2-ethoxyethyl ether (EEE), sulfone, sulfolane, dimethylcarbonate (DMC), methylethyl carbonate (MEC), ethyl propionate, methylpropionate, propylene carbonate (PC), gamma.-butyrolactone (γ-BL),acetonitrile (AN), ethyl acetate (EA), propyl formate (PF), methylformate (MF), toluene, xylene, methyl acetate (MA), fluoroethylenecarbonate (FEC), vinylene carbonate (VC), allyl ethyl carbonate (AEC),or a combination thereof.

The first or the second liquid solvents may include fluorinated monomershaving unsaturation (double bonds or triple bonds that can be opened upfor polymerization); e.g., fluorinated vinyl carbonates, fluorinatedvinyl monomers, fluorinated esters, fluorinated vinyl esters, andfluorinated vinyl ethers). Fluorinated vinyl esters includeR_(f)CO₂CH═CH₂ and Propenyl Ketones, R_(f)COCH═CHCH₃, where Rr is F orany F-containing functional group (e.g., CF₂— and CF₂CF₃—).

Two examples of fluorinated vinyl carbonates are given below:

These liquid solvents can be cured in the presence of an initiator(e.g., 2-Hydroxy-2-methyl-1-phenyl-propan-1-one, Ciba DAROCUR-1173,which can be activated by UV or electron beam) if so desired:

In some embodiments, the fluorinated carbonate is selected from vinyl-or double bond-containing variants of fluoroethylene carbonate (FEC),DFDMEC, FNPEC, hydrofluoro ether (HFE), trifluoro propylene carbonate(FPC), methyl nonafluorobutyl ether (MFE), or a combination thereof,wherein the chemical formulae for FEC, DFDMEC, and FNPEC, respectivelyare shown below:

Desirable sulfones as a first or second liquid solvent include, but notlimited to, alkyl and aryl vinyl sulfones or sulfides; e.g., ethyl vinylsulfide, allyl methyl sulfide, phenyl vinyl sulfide, phenyl vinylsulfoxide, ethyl vinyl sulfone, allyl phenyl sulfone, allyl methylsulfone, and divinyl sulfone:

Simple alkyl vinyl sulfones, such as ethyl vinyl sulfone, may bepolymerized via emulsion and bulk methods. Propyl vinyl sulfone may bepolymerized by alkaline persulfate initiators to form soft polymers. Itmay be noted that aryl vinyl sulfone, e.g., naphthyl vinyl sulfone,phenyl vinyl sulfone, and parra-substituted phenyl vinyl sulfone (R=NH₂,NO₂ or Br), were reported to be unpolymerizable with free-radicalinitiators. However, we have observed that phenyl and methyl vinylsulfones can be polymerized with several anionic-type initiators.Effective anionic-type catalysts or initiators are n-BuLi, ZnEt2,LiN(CH₂)₂, NaNH₂, and complexes of n-LiBu with ZnEt2 or AlEh. A secondsolvent, such as pyridine, sulfolane, toluene or benzene, can be used todissolve alkyl vinyl sulfones, aryl vinyl sulfones, and other largersulfone molecules.

Poly(sulfone)s have high oxygen indices and low smoke emission onburning. Poly(sulfone)s are inherently self-extinguishing materialsowing to their highly aromatic character. In certain embodiments, thesulfone as a first or the second liquid solvent is selected from TrMS,MTrMS, TMS, or vinyl or double bond-containing variants of TrMS, MTrMS,TMS, EMS, MMES, EMES, EMEES, or a combination thereof; their chemicalformulae being given below:

The cyclic structure, such as TrMS, MTrMS, and TMS, can be polymerizedvia ring-opening polymerization with the assistance of an ionic typeinitiator.

The first or the second liquid solvent may be a nitrile preferablyselected from dinitriles, such as AND, GLN, and SEN, which have thefollowing chemical formulae:

In some embodiments, the phosphate, phosphonate, phosphazene, phosphite,or sulfate, as a first liquid solvent or in the second liquid solvent,is selected from tris(trimethylsilyl) phosphite (TTSPi), alkylphosphate, triallyl phosphate (TAP), ethylene sulfate (DTD), acombination thereof. The phosphate, alkyl phosphonate, or phosphazenemay be selected from the following:

The phosphate, alkyl phosphonate, phosphonic acid, and phosphazene areflame-resistant. Good examples include diethyl vinylphosphonate,dimethyl vinylphosphonate, vinylphosphonic acid, diethyl allylphosphate, and diethyl allylphosphonate:

The siloxane or silane in the second liquid solvent may be selected fromalkylsiloxane (Si—O), alkyylsilane (Si—C), liquid oligomeric silaxane(—Si—O—Si—), or a combination thereof.

The reactive additive may further comprise an amide group selected fromN,N-dimethylacetamide, N,N-diethylacetamide, N,N-dimethylformamide,N,N-diethylformamide, or a combination thereof.

In certain embodiments, the crosslinking agent comprises a compoundhaving at least one reactive group selected from a hydroxyl group, anamino group, an imino group, an amide group, an acrylic amide group, anamine group, an acrylic group, an acrylic ester group, or a mercaptogroup in the molecule.

In certain embodiments, the crosslinking agent is selected frompoly(diethanol) diacrylate, poly(ethyleneglycol)dimethacrylate,poly(diethanol) dimethylacrylate, poly(ethylene glycol) diacrylate,lithium hexafluorophosphate (LiPF₆), lithium borofluoride (LiBF₄),lithium hexafluoroarsenide (LiAsF₆), lithium trifluoro-metasulfonate(LiCF₃SO₃), bis-trifluoromethyl sulfonylimide lithium (LiN(CF₃SO₂)₂),lithium bis(oxalato)borate (LiBOB), lithium oxalyldifluoroborate(LiBF₂C₂O₄), lithium oxalyldifluoroborate (LiBF₂C₂O₄), or a combinationthereof.

The initiator may be selected from an azo compound (e.g.,azodiisobutyronitrile, AIBN), azobisisobutyronitrile,azobisisoheptonitrile, dimethyl azobisisobutyrate, benzoyl peroxidetert-butyl peroxide and methyl ethyl ketone peroxide, benzoyl peroxide(BPO), bis(4-tert-butylcyclohexyl)peroxydicarbonate, t-amylperoxypivalate, 2,2′-azobis-(2,4-dimethylvaleronitrile),2,2′-azobis-(2-methylbutyronitrile),1,1-azobis(cyclohexane-1-carbonitrile, benzoylperoxide (BPO), hydrogenperoxide, dodecamoyl peroxide, isobutyryl peroxide, cumenehydroperoxide, tert-butyl peroxypivalate, diisopropyl peroxydicarbonate,or a combination thereof.

In the disclosed polymer electrolyte, the lithium salt may be selectedfrom lithium perchlorate (LiClO₄), lithium hexafluorophosphate (LiPF₆),lithium borofluoride (LiBF₄), lithium hexafluoroarsenide (LiAsF₆),lithium trifluoro-metasulfonate (LiCF₃SO₃), bis-trifluoromethylsulfonylimide lithium (LiN(CF₃SO₂)₂), lithium bis(oxalato)borate(LiBOB), lithium oxalyldifluoroborate (LiBF₂C₂O₄), lithiumoxalyldifluoroborate (LiBF₂C₂O₄), lithium nitrate (LiNO₃),Li-Fluoroalkyl-Phosphates (LiPF₃(CF₂CF₃)₃), lithiumbisperfluoro-ethysulfonylimide (LiBETI), lithiumbis(trifluoromethanesulphonyl)imide, lithium bis(fluorosulphonyl)imide,lithium trifluoromethanesulfonimide (LiTFSI), an ionic liquid lithiumsalt, or a combination thereof.

The cathode in the disclosed lithium cell typically comprises particlesof a cathode active material and the electrolyte permeates into thecathode to come in physical contact with substantially all the cathodeactive material particles.

In some preferred embodiments, the battery cell contains substantiallyno liquid solvent left therein (substantially >99% of the liquid solventbeing polymerized to become a polymer). However, it is essential toinitially include a liquid solvent in the cell, enabling the lithiumsalt to get dissociated into lithium ions and anions. A majority (>50%,preferably >70%) or substantially all of the liquid solvents is thencured (polymerized or crosslinked). With less than 1% liquid solvent,the resulting electrolyte is a solid-state electrolyte. With less than30% liquid solvent, we have a quasi-solid electrolyte. Both are highlyflame-resistant.

A lower proportion of the liquid solvent in the electrolyte leads to asignificantly reduced vapor pressure and increased flash point orcompletely eliminated flash point (un-detectable). Although typically byreducing the liquid solvent proportion one tends to observe a reducedlithium ion conductivity for the resulting electrolyte; however, quitesurprisingly, after a threshold liquid solvent fraction, this trend isdiminished or reversed (the lithium ion conductivity can actuallyincrease with reduced liquid solvent in some cases).

The crosslinking agent preferably comprises a compound having at leastone reactive group selected from a hydroxyl group, an amino group, animino group, an amide group, an amine group, an acrylic group, or amercapto group in the molecule. In some desired embodiments, thecrosslinking agent may be selected from a chemical species representedby Chemical formula 1 below:

where R₄ and R₅ are each independently hydrogen or methyl group, and nis an integer from 3 to 30, wherein R′ is C₁-C₅ alkyl group.

In some embodiments, the crosslinking agent may be selected fromN,N-methylene bisacrylamide, epichlorohydrin, 1,4-butanediol diglycidylether, tetrabutylammonium hydroxide, cinnamic acid, ferric chloride,aluminum sulfate octadecahydrate, diepoxy, dicarboxylic acid compound,poly(potassium 1-hydroxy acrylate) (PKHA), glycerol diglycidyl ether(GDE), ethylene glycol, polyethylene glycol, polyethylene glycoldiglycidyl ether (PEGDE), citric acid, acrylic acid, methacrylic acid, aderivative compound of acrylic acid, a derivative compound ofmethacrylic acid, glycidyl functions, N,N′-Methylenebisacrylamide(MBAAm), Ethylene glycol dimethacrylate (EGDMAAm), isobornylmethacrylate, poly (acrylic acid) (PAA), methyl methacrylate, isobornylacrylate, ethyl methacrylate, isobutyl methacrylate, n-Butylmethacrylate, ethyl acrylate, 2-Ethyl hexyl acrylate, n-Butyl acrylate,a diisocyanate, an urethane chain, a chemical derivative thereof, or acombination thereof.

The polymer in the electrolyte may form a mixture, copolymer,semi-interpenetrating network, or simultaneous interpenetrating networkwith a second polymer selected from poly(ethylene oxide), polypropyleneoxide, poly(ethylene glycol), poly(acrylonitrile), poly(methylmethacrylate), poly(vinylidene fluoride), poly bis-methoxyethoxyethoxide-phosphazenex, polyvinyl chloride, polydimethylsiloxane,poly(vinylidene fluoride)-hexafluoropropylene (PVDF-HFP), cyanoethylpoly(vinyl alcohol), a pentaerythritol tetraacrylate-based polymer, analiphatic polycarbonate, a single Li-ion conducting solid polymerelectrolyte with a carboxylate anion, a sulfonylimide anion, orsulfonate anion, a crosslinked electrolyte of poly(ethylene glycol)diacrylate or poly(ethylene glycol) methyl ether acrylate, a sulfonatedderivative thereof, or a combination thereof. This second polymer may bepre-mixed into an anode and/or a cathode. Alternatively, this secondpolymer may be dissolved in the liquid solvent where appropriate orpossible to form a solution prior to being injected into the batterycell.

In certain desirable embodiments, the electrolyte further comprisesparticles of an inorganic solid electrolyte material having a particlesize from 2 nm to 30 μm, wherein the particles of inorganic solidelectrolyte material are dispersed in the polymer or chemically bondedby the polymer. The particles of inorganic solid electrolyte materialare preferably selected from an oxide type, sulfide type, hydride type,halide type, borate type, phosphate type, lithium phosphorus oxynitride(LiPON), garnet-type, lithium superionic conductor (LISICON) type,sodium superionic conductor (NASICON) type, or a combination thereof.Such a composite composition is of particular utility value for use as asolid electrolyte separator disposed between an anode and a cathode.

The rechargeable lithium cell may further comprise a separator disposedbetween the anode and the cathode. Preferably, the separator comprises aquasi-solid or solid-state electrolyte as herein disclosed.

The separator may comprise the presently disclosed electrolyte. Incertain embodiments, the separator comprises polymeric fibers, ceramicfibers, glass fibers, or a combination thereof. These fibers may bestacked together in such a manner that there are pores that allow forpermeation of lithium ions, but not for penetration of any potentiallyformed lithium dendrites. These fibers may be dispersed in a matrixmaterial or bonded by a binder material. This matrix or binder materialmay contain a ceramic or glass material. The polymer electrolyte mayserve as the matrix material or binder material that helps to hold thesefibers together. The separator may contain particles of a glass orceramic material (e.g., metal oxide, metal carbide, metal nitride, metalboride, etc.).

The present disclosure further provides a rechargeable lithium battery,including a lithium metal secondary cell, a lithium-ion cell, alithium-sulfur cell, a lithium-ion sulfur cell, a lithium-selenium cell,or a lithium-air cell. This battery features a non-flammable, safe, andhigh-performing electrolyte as herein disclosed.

The polymerizable first liquid solvent in the reactive additive orelectrolyte composition may be initially in a liquid monomer state,which can be injected into an electrode (e.g., a cathode) or a batterycell and then cured (polymerized and/or crosslinked) in situ inside theelectrode or the cell.

Alternatively, the reactive liquid solvent electrolyte composition(comprising the needed lithium salt and an initiator and/or acrosslinking agent) may be mixed with an electrode active material(e.g., cathode active material particles, such as NCM, NCA and lithiumiron phosphate), a conducting additive (e.g., carbon black, carbonnanotubes, expanded graphite flakes, or graphene sheets), and anoptional flame-retardant agent and/or optional particles of an inorganicsolid electrolyte to form a reactive slurry or paste. The slurry orpaste is then made into a desired electrode shape (e.g., cathodeelectrode), possibly supported on a surface of a current collector(e.g., an Al foil as a cathode current collector). An anode of alithium-ion cell may be made in a similar manner using an anode activematerial (e.g., particles of graphite, Si, SiO, etc.). The anodeelectrode, a cathode electrode, and an optional separator are thencombined to form a battery cell. The reactive solvent inside the cell isthen polymerized and/or crosslinked in situ inside the battery cell.

The electrolyte composition is designed to permeate into the internalstructure of the cathode and to be in physical contact or ionic contactwith the cathode active material in the cathode, and to permeate intothe anode electrode to be in physical contact or ionic contact with theanode active material where/if present.

The flash point of the quasi-solid electrolyte is typically at least 100degrees higher than the flash point of the same organic liquid solventwithout being polymerized. In most of the cases, either the flash pointis higher than 200° C. or no flash point can be detected. Theelectrolyte just would not catch on fire or get ignited. Anyaccidentally initiated flame does not sustain for longer than a fewseconds. This is a highly significant discovery, considering the notionthat fire and explosion concern has been a major impediment towidespread acceptance of battery-powered electric vehicles. This newtechnology could potentially reshape the landscape of EV industry.

Still another preferred embodiment of the present disclosure is arechargeable lithium-sulfur cell or lithium-ion sulfur cell containing asulfur cathode having sulfur or lithium polysulfide as a cathode activematerial.

For a lithium metal cell (where lithium metal is the primary activeanode material), the anode current collector may comprise a foil,perforated sheet, or foam of a metal having two primary surfaces whereinat least one primary surface is coated with or protected by a layer oflithiophilic metal (a metal capable of forming a metal-Li solid solutionor is wettable by lithium ions), a layer of graphene material, or both.The metal foil, perforated sheet, or foam is preferably selected fromCu, Ni, stainless steel, Al, graphene-coated metal, graphite-coatedmetal, carbon-coated metal, or a combination thereof. The lithiophilicmetal is preferably selected from Au, Ag, Mg, Zn, Ti, K, Al, Fe, Mn, Co,Ni, Sn, V, Cr, an alloy thereof, or a combination thereof.

For a lithium ion battery featuring the presently disclosed electrolyte,there is no particular restriction on the selection of an anode activematerial. The anode active material may be selected from the groupconsisting of: (a) silicon (Si), germanium (Ge), tin (Sn), lead (Pb),antimony (Sb), phosphorus (P), bismuth (Bi), zinc (Zn), aluminum (Al),titanium (Ti), nickel (Ni), cobalt (Co), and cadmium (Cd); (b) alloys orintermetallic compounds of Si, Ge, Sn, Pb, Sb, Bi, Zn, Al, Ti, Ni, Co,or Cd with other elements; (c) oxides, carbides, nitrides, sulfides,phosphides, selenides, and tellurides of Si, Ge, Sn, Pb, Sb, Bi, Zn, Al,Ti, Fe, Ni, Co, V, or Cd, and their mixtures, composites, orlithium-containing composites; (d) salts and hydroxides of Sn; (e)lithium titanate, lithium manganate, lithium aluminate, lithium titaniumniobate, lithium-containing titanium oxide, lithium transition metaloxide, ZnCo₂O₄; (f) carbon or graphite particles (g) prelithiatedversions thereof; and (h) combinations thereof.

In some embodiments, the anode active material contains a prelithiatedSi, prelithiated Ge, prelithiated Sn, prelithiated SnO_(x), prelithiatedSiO_(x), prelithiated iron oxide, prelithiated V₂O₅, prelithiated V₃O₈,prelithiated Co₃O₄, prelithiated Ni₃O₄, or a combination thereof,wherein x=1 to 2.

The rechargeable lithium cell may further comprise a cathode currentcollector selected from aluminum foil, carbon- or graphene-coatedaluminum foil, stainless steel foil or web, carbon- or graphene-coatedsteel foil or web, carbon or graphite paper, carbon or graphite fiberfabric, flexible graphite foil, graphene paper or film, or a combinationthereof. A web means a screen-like structure or a metal foam, preferablyhaving interconnected pores or through-thickness apertures.

The present disclosure also provides a reactive electrolyte compositioncomprising (i) a first liquid solvent that is polymerizable, (ii) aninitiator or curing agent, (iii) a lithium salt, and (iv) a secondliquid solvent comprising an ionic liquid; wherein the first liquidsolvent occupies from 1% to 99% by weight and the second solventoccupies from 0.1% to 99% by weight based on the total weight of thereactive electrolyte composition; wherein the first liquid solvent has alower flash point, a higher vapor pressure, or a higher solubility ofthe lithium salt as compared with the second liquid solvent.

In this reactive electrolyte composition, the first liquid solvent ispreferably selected from vinylene carbonate, ethylene carbonate,fluoro-ethylene carbonate, vinyl sulfite, vinyl ethylene sulfite, vinylethylene carbonate, 1,3-propyl sultone, 1,3-acrylic-sultones, methylethylene sulfone, methyl vinyl sulfone, ethyl vinyl sulfone, methylmethacrylate, vinyl acetate, acrylamide, 1,3-dioxolane (DOL), afluorinated vinyl carbonate, fluorinated vinyl monomer, fluorinatedester, fluorinated vinyl ester, fluorinated vinyl ether, or acombination thereof.

The second liquid solvent in this reactive electrolyte composition ispreferably selected from the group consisting of fluorinated ethers,fluorinated esters, sulfones, sulfides, nitriles, sulfates, siloxanes,silanes, combinations thereof, and combinations with phosphates,phosphonates, phosphinates, phosphines, phosphine oxides, phosphonicacids, phosphorous acid, phosphites, phosphoric acids, phosphazenecompounds, derivatives thereof, and combinations thereof.

The present disclosure also provides a method of producing the disclosedrechargeable lithium cell, the method comprising: (a) combining ananode, an optional separator layer, a cathode, and a protective housingto form a cell; (b) introducing a reactive liquid electrolytecomposition into the cell, wherein the reactive liquid electrolytecomposition comprises at least a polymerizable first liquid solvent, alithium salt dissolved in the first liquid solvent, a crosslinking agentand/or an initiator, and a second liquid solvent, wherein the firstliquid solvent occupies from 1% to 99% by weight and the second liquidsolvent occupies from 0.1% to 99% by weight based on the total weight ofthe reactive liquid electrolyte composition and the first liquid solventhas a lower flash point (higher flammability), a higher vapor pressure,a higher dielectric constant, or a higher solubility of the lithium saltas compared with the second liquid solvent; and (c) partially or totallypolymerizing the first liquid solvent to obtain a quasi-solid orsolid-state electrolyte wherein from 30% to 100% by weight of thepolymerizable first liquid solvent is polymerized.

Preferably, the first liquid solvent is selected from the groupconsisting of vinylene carbonate, ethylene carbonate, fluoroethylenecarbonate, vinyl sulfite, vinyl ethylene sulfite, vinyl ethylenecarbonate, 1,3-propyl sultone, 1,3,5-trioxane (TXE),1,3-acrylic-sultones, methyl ethylene sulfone, methyl vinyl sulfone,ethyl vinyl sulfone, methyl methacrylate, vinyl acetate, acrylamide,1,3-dioxolane (DOL), fluorinated ethers, fluorinated esters, sulfones,sulfides, dinitriles, acrylonitrile (AN), sulfates, siloxanes, silanes,N-methylacetamide, acrylates, ethylene glycols, phosphates,phosphonates, phosphinates, phosphines, phosphine oxides, phosphonicacids, phosphorous acid, phosphites, phosphoric acids, phosphazenecompounds, derivatives thereof, and combinations thereof.

Preferably, Step (c) either does not polymerize the second liquidsolvent or polymerizes the second liquid solvent to a different extentas compared to the polymerizable first liquid solvent.

The disclosure further provides a method of producing the rechargeablelithium cell, the method comprising: (A) mixing particles of a cathodeactive material, an optional conductive additive, an optional binder,and a reactive additive to form a cathode, wherein the reactive additivecomprises (i) a first liquid solvent that is polymerizable, (ii) aninitiator or curing agent, (iii) a lithium salt, and (iv) a secondliquid solvent comprising an ionic liquid; wherein the first liquidsolvent occupies from 1% to 99% by weight based on the total weight ofthe reactive additive and wherein the first liquid solvent has a lowerflash point, a higher vapor pressure, or a higher solubility of thelithium salt as compared with the second liquid solvent; (B) providingan anode; (C) combining the cathode, a separator, and the anode to forma cell; and (D) partially or totally polymerizing the first solvent,prior to or after step (C), to produce the rechargeable lithium cell,wherein at least 30% by weight of the first liquid solvent ispolymerized.

In some embodiments, step (B) comprises a procedure of mixing particlesof an anode active material, an optional conductive additive, anoptional binder, a reactive additive, and a lithium salt to form ananode, wherein the reactive additive comprises at least a polymerizableliquid solvent, a crosslinking agent or initiator, and a second liquidsolvent and wherein the method further comprises polymerizing and/orcrosslinking the reactive additive, prior to or after step (C), toproduce the rechargeable lithium cell. Step (A) may further compriseadding particles of an inorganic solid electrolyte powder in the cathodeor in the anode.

For all the methods, the first liquid solvent and the second liquidsolvent typically are polymerized and/or crosslinked to differentextents even under the same conditions. The second liquid solvent may bechosen to be non-polymerizable.

The procedure of polymerizing and/or crosslinking may comprise exposingthe reactive additive to heat, UV, high-energy radiation, or acombination thereof. The high-energy radiation may be selected fromelectron beam, Gamma radiation, X-ray, neutron radiation, etc. Electronbeam irradiation is particularly useful.

These and other advantages and features of the present disclosure willbecome more transparent with the description of the following best modepractice and illustrative examples.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1(A) A process flow chart to illustrate a method of producing alithium metal battery comprising a substantially solid-state electrolyte(all solid-state and quasi-solid electrolytes) according to someembodiments of the present disclosure;

FIG. 1(B) A process flow chart to illustrate the method of producing areactive electrolyte composition according to some embodiments of thepresent disclosure;

FIG. 1(C) A process flow chart to illustrate a method of producing alithium metal battery comprising a substantially solid-state electrolyteaccording to some embodiments of the present disclosure;

FIG. 1(D) A process flow chart to illustrate a method of producing alithium metal battery comprising a substantially solid-state electrolyteaccording to some embodiments of the present disclosure.

FIG. 2(A) Structure of an anode-less lithium metal cell (as manufacturedor in a discharged state) according to some embodiments of the presentdisclosure;

FIG. 2(B) Structure of an anode-less lithium metal cell (in a chargedstate) according to some embodiments of the present disclosure.

DETAILED DESCRIPTION

The present disclosure provides a safe and high-performing lithiumbattery, which can be any of various types of lithium-ion cells orlithium metal cells. A high degree of safety is imparted to this batteryby a novel and unique electrolyte that is highly flame-resistant andwould not initiate a fire or sustain a fire and, hence, would not poseexplosion danger. This disclosure has solved the very most criticalissue that has plagued the lithium-metal and lithium-ion industries formore than two decades.

As indicated earlier in the Background section, a strong need exists fora safe, non-flammable, yet injectable quasi-solid electrolyte orsolid-state electrolyte system for a rechargeable lithium cell that iscompatible with existing battery production facilities. It is well-knownin the art that the conventional solid-state electrolyte batteriestypically cannot be produced using existing lithium-ion batteryproduction equipment or processes.

The present disclosure provides a rechargeable lithium batterycomprising an anode, a cathode, and a hybrid quasi-solid or solid-stateelectrolyte in ionic communication with the anode and the cathode,wherein the hybrid electrolyte, having a lithium ion conductivityapproximately from 10⁻⁵ S/cm to 5×10⁻² S/cm, comprises particles of aninorganic solid electrolyte (ISE) material dispersed in or bonded by apolymer, which is a polymerization or crosslinking product of a reactiveadditive, wherein the reactive additive comprises (i) a first liquidsolvent that is polymerizable, (ii) an initiator or curing agent, (iii)a lithium salt, and (iv) an optional second liquid solvent (e.g., thesecond liquid solvent comprising an ionic liquid, preferably a roomtemperature ionic liquid); wherein the first liquid solvent occupiesfrom 1% to 99% by weight and the second liquid electrolyte occupies from0.1% to 99% by weight based on the total weight of the reactiveadditive; and wherein the polymer alone or the hybrid electrolyte ispresent in the anode, the cathode, the separator, between the anode andthe separator, or between the cathode and the separator.

Preferably, at least 20% by weight of the polymerizable first liquidsolvent is polymerized; more preferably >50%, further preferably >70%,and most preferably >99% is polymerized. The ISE-to-polymer electrolytevolume ratio can be from 1/99 to 99/1, but typically from 5/95 to 95/5,more typically from 10/90 to 90/10, further more typically from 20/80 to80/20, and most typically from 30/70 to 70/30. Preferably, the firstliquid solvent has a lower flash point (higher flammability), a highervapor pressure, or a higher solubility of the lithium salt as comparedwith the second liquid solvent;

In certain embodiments, the particles of an inorganic solid electrolytematerial have a particle size from 2 nm to 30 μm and are dispersed inthe polymer or chemically bonded by the polymer. The particles ofinorganic solid electrolyte material are preferably selected from anoxide type, sulfide type, hydride type, halide type, borate type,phosphate type, lithium phosphorus oxynitride (LiPON), garnet-type,lithium superionic conductor (LISICON) type, sodium superionic conductor(NASICON) type, or a combination thereof.

The inorganic solid electrolyte particles that can be incorporated intothe hybrid electrolyte include, but are not limited to, perovskite-type.NASICON-type, garnet-type and sulfide-type materials. A representativeand well-known perovskite solid electrolyte is Li_(3x)La_(2/3−x)TiO₃,which exhibits a lithium-ion conductivity exceeding 10⁻³ S/cm at roomtemperature. This material has been deemed unsuitable in lithiumbatteries because of the reduction of Ti on contact with lithium metal.However, we have found that this material, when dispersed in a polymer,does not suffer from this problem.

The sodium superionic conductor (NASICON)-type compounds include awell-known Na_(1+x)Zr₂Si_(x)P_(3−x)O₁₂. These materials generally havean AM₂(PO₄)₃ formula with the A site occupied by Li, Na or K. The M siteis usually occupied by Ge, Zr or Ti. In particular, the LiTi₂(PO₄)₃system has been widely studied as a solid-state electrolyte for thelithium-ion battery. The ionic conductivity of LiZr₂(PO₄)₃ is very low,but can be improved by the substitution of Hf or Sn. This can be furtherenhanced with substitution to form Li_(1+x)M_(x)Ti_(2−x)(PO₄)₃ (M=Al,Cr, Ga. Fe, Sc, In, Lu, Y or La). Al substitution has been demonstratedto be the most effective solid-state electrolyte. TheLi_(1+x)Al_(x)Ge_(2−x)(PO₄)₃ system is also an effective solid state dueto its relatively wide electrochemical stability window. NASICON-typematerials are considered as suitable solid electrolytes for high-voltagesolid electrolyte batteries.

Garnet-type materials have the general formula A₃B₂Si₃O₁₂, in which theA and B cations have eightfold and sixfold coordination, respectively.In addition to Li₃M₂Ln₃O₁₂ (M=W or Te), a broad series of garnet-typematerials may be used as an additive, including Li₅La₃M₂O₁₂ (M=Nb orTa), Li₆ALa₂M₂O₁₂ (A=Ca, Sr or Ba; M=Nb or Ta),Li_(5.5)La₃M_(1.75)B_(0.25)O₁₂ (M=Nb or Ta; B=In or Zr) and the cubicsystems Li₇La₃Zr₂O₁₂ and Li_(7.06)M₃Y_(0.06)Zr_(1.94)O₁₂ (M=La, Nb orTa). The Li_(6.5)La₃Zr_(1.75)Te_(0.25)O₁₂ compounds have a high ionicconductivity of 1.02×10⁻³ S/cm at room temperature.

The sulfide-type solid electrolytes include the Li₂S—SiS₂ system. Theconductivity in this type of material is 6.9×10⁻⁴ S/cm, which wasachieved by doping the Li₂S—SiS₂ system with Li₃PO₄. Other sulfide-typesolid-state electrolytes can reach a good lithium-ion conductivity closeto 10⁻² S/cm. The sulfide type also includes a class of thio-LISICON(lithium superionic conductor) crystalline material represented by theLi₂S—P₂S₅ system. The chemical stability of the Li₂S—P₂S₅ system isconsidered as poor, and the material is sensitive to moisture(generating gaseous H₂S). The stability can be improved by the additionof metal oxides. The stability is also significantly improved if theLi₂S—P₂S₅ material is dispersed in an elastic polymer.

These inorganic solid electrolyte (ISE) particles dispersed in anelectrolyte polymer can help enhance the lithium ion conductivity ofcertain polymers that have a lower ion conductivity. Preferably andtypically, the polymer electrolyte (with or with an uncured solvent) hasa lithium ion conductivity no less than 10⁻⁵ S/cm, more preferably noless than 10⁻⁴ S/cm, further preferably no less than 10⁻³ S/cm, and mostpreferably no less than 10⁻² S/cm.

It should be noted that certain inorganic solid electrolytes (e.g.,sulfide type ISE) can have a higher lithium-ion conductivity as comparedto certain selected in situ curable polymers. However, it would normallytake a large proportion of the particles of an inorganic solidelectrolyte (e.g., >50% by volume) to reach a contiguous phase in ananode or a cathode. This implies that the proportion of an activematerial (responsible for storing lithium ions) would be significantlyreduced (e.g., less than 50%), hence, resulting in an undesirably lowenergy density. To overcome such a design deficiency, we choose toimplement a smaller fraction of a highly ion conducting ISE (e.g.,3%-25% vs. 25-50% by volume relative to the volume of an entireelectrode) when an electrode (anode or cathode) is made. In thissituation, the ISE particles alone do not constitute a contiguous phase(continuous or contiguous ion-conducting pathways). However, we canachieve a contiguous phase by combining ISE particles and apolymerizable liquid electrolyte; the liquid electrolyte being capableof permeating into the electrode, wetting surfaces of the ISE particles,and ionically connecting isolated ISE particles together. The liquidelectrolyte (having a lithium salt dissolved in a liquid solvent) isthen cured (polymerized and/or crosslinked) after the electrode is madeor after the battery cell is produced. Such a strategy enables theformation of a contiguous electrolyte phase (allowing lithium ions toreach all the electrode active material particles) with a minimalfraction of electrolyte (hence, higher proportion of the desired activematerial and higher energy density).

In certain embodiments, the first liquid solvent is selected from thegroup consisting of vinylene carbonate, ethylene carbonate,fluoroethylene carbonate, vinyl sulfite, vinyl ethylene sulfite, vinylethylene carbonate, 1,3-propyl sultone, 1,3,5-trioxane (TXE),1,3-acrylic-sultones, methyl ethylene sulfone, methyl vinyl sulfone,ethyl vinyl sulfone, methyl methacrylate, vinyl acetate, acrylamide,1,3-dioxolane (DOL), fluorinated ethers, fluorinated esters, sulfones,sulfides, dinitriles, acrylonitrile (AN), sulfates, siloxanes, silanes,N-methylacetamide, acrylates, ethylene glycols, phosphates,phosphonates, phosphinates, phosphines, phosphine oxides, phosphonicacids, phosphorous acid, phosphites, phosphoric acids, phosphazenecompounds, ionic liquids, derivatives thereof, and combinations thereof.The optional second liquid solvent may comprise an ionic liquid.

The ionic liquid is typically composed of ions only. Ionic liquids arelow melting temperature salts that are in a molten or liquid state whenabove a desired temperature. For instance, an ionic salt is consideredas an ionic liquid if its melting point is below 100° C. If the meltingtemperature is equal to or lower than room temperature (25° C.), thesalt is referred to as a room temperature ionic liquid (RTIL). TheIL-based lithium salts are characterized by weak interactions, due tothe combination of a large cation and a charge-delocalized anion. Thisresults in a low tendency to crystallize due to flexibility (anion) andasymmetry (cation).

Some ILs may be used as a co-solvent (not as a salt) to work with thefirst organic solvent of the present disclosure. A well-known ionicliquid is formed by the combination of a 1-ethyl-3-methyl-imidazolium(EMI) cation and an N,N-bis(trifluoromethane)sulphonamide (TFSI) anion.This combination gives a fluid with an ionic conductivity comparable tomany organic electrolyte solutions, a low decomposition propensity andlow vapor pressure up to ˜300-400° C. This implies a generally lowvolatility and non-flammability and, hence, a much safer electrolytesolvent for batteries.

Ionic liquids are basically composed of organic or inorganic ions thatcome in an unlimited number of structural variations owing to thepreparation ease of a large variety of their components. Thus, variouskinds of salts can be used to design the ionic liquid that has thedesired properties for a given application. These include, among others,imidazolium, pyrrolidinium and quaternary ammonium salts as cations andbis(trifluoromethanesulphonyl) imide, bis(fluorosulphonyl)imide andhexafluorophosphate as anions. Useful ionic liquid-based lithium salts(not solvent) may be composed of lithium ions as the cation andbis(trifluoromethanesulphonyl)imide, bis(fluorosulphonyl)imide andhexafluorophosphate as anions. For instance, lithiumtrifluoromethanesulfonimide (LiTFSI) is a particularly useful lithiumsalt.

Based on their compositions, ionic liquids come in different classesthat include three basic types: aprotic, protic and zwitterionic types,each one suitable for a specific application. Common cations of roomtemperature ionic liquids (RTILs) include, but are not limited to,tetraalkylammonium, di, tri, and tetra-alkylimidazolium,alkylpyridinium, dialkyl-pyrrolidinium, dialkylpiperidinium,tetraalkylphosphonium, and trialkylsulfonium. Common anions of RTILsinclude, but are not limited to, BF₄ ⁻, B(CN)₄ ⁻, CH₃BF₃ ⁻, CH₂CHBF₃ ⁻,CF₃BF₃ ⁻, C₂F₅BF₃ ⁻, n-C₃F₇BF₃ ⁻, n-C₄F₉BF₃ ⁻, PF₆ ⁻, CF₃CO₂ ⁻, CF₃SO₃⁻, N(SO₂CF₃)₂ ⁻, N(COCF₃)(SO₂CF₃)⁻, N(SO₂F)₂ ⁻, N(CN)₂ ⁻, C(CN)₃ ⁻,SCN⁻, SeCN⁻, CuCl₂ ⁻, AlCl₄ ⁻, F(HF)_(2.3) ⁻, etc. Relatively speaking,the combination of imidazolium- or sulfonium-based cations and complexhalide anions such as AlCl₄ ⁻, BF₄ ⁻, CF₃CO₂ ⁻, CF₃SO₃ ⁻, NTf₂ ⁻,N(SO₂F)₂ ⁻, or F(HF)_(2.3) ⁻ results in RTILs with good workingconductivities.

RTILs can possess archetypical properties such as high intrinsic ionicconductivity, high thermal stability, low volatility, low (practicallyzero) vapor pressure, non-flammability, the ability to remain liquid ata wide range of temperatures above and below room temperature, highpolarity, high viscosity, and wide electrochemical windows. Theseproperties, except for the high viscosity, are desirable attributes whenit comes to using an RTIL as an electrolyte co-solvent in a rechargeablelithium cell.

In the conventional lithium-ion battery or lithium metal batteryindustry, the first liquid solvents listed above are commonly used as asolvent to dissolve a lithium salt therein and the resulting solutionsare used as a liquid electrolyte. These liquid solvents are typicallycapable of dissolving a high amount of a lithium salt; however, they aretypically highly volatile, having a low flash point and being highlyflammable. Further, these liquid solvents are generally not known to bepolymerizable, with or without the presence of a second liquid solvent,and a separate or different polymer or monomer is typically used in theindustry to prepare a gel polymer electrolyte or solid polymerelectrolyte.

It is highly advantageous to be able to polymerize the liquid solventonce the liquid electrolyte (having a lithium salt dissolved in thefirst liquid solvent) is injected into an electrode or into a batterycell. The lithium salt is readily dissociated into lithium ions andcorresponding anions, which could remain separated and dispersed in amatrix of polymer chains. With such an innovative strategy, one canreadily reduce the liquid solvent or completely eliminate the volatileliquid solvent all together. A desired amount of a second liquidsolvent, containing an ionic liquid or a flame-resistant liquid solvent,may be retained in the battery cell to improve the lithium ionconductivity of the electrolyte. Desirable flame retardant-type liquidsolvents are, as examples, alkyl phosphates, alkyl phosphonates,phosphazenes, hydrofluoroethers, fluorinated ethers, and fluorinatedesters.

This strategy enables us to achieve several desirable features of theresultant hybrid electrolytes and batteries:

-   -   a) no liquid electrolyte leakage issue (the in situ cured        polymer being capable of holding any remaining liquid together        to form a gel or solvent-in-polymer state);    -   b) adequate lithium salt amount can be dissolved in the polymer        electrolyte, enabling a good lithium ion conductivity;    -   c) reduced or eliminated flammability (only a hybrid ISE/polymer        solid and an optional non-flammable second liquid are retained        in the cell);    -   d) good ability of the electrolyte to wet the surfaces of        anode/cathode active materials (hence, significantly reduced        interfacial impedance and internal resistance);    -   e) processing ease and compatibility with current lithium-ion        battery production processes and equipment; and    -   f) enabling a high cathode active material proportion in the        cathode electrode (typically 75-97%, in contrast to typically        less than 75% by weight of the cathode active material when        working with a conventional solid polymer electrolyte or        inorganic solid electrolyte. This strategy also enables a high        anode active material proportion when particles of an anode        active material are used.        This disclosed in situ-cured polymer electrolyte approach is of        significant utility value since most of the organic solvents are        known to be volatile and flammable, posing a fire and explosion        danger. Further, current solid-state electrolytes are not        compatible with existing lithium-ion battery manufacturing        equipment and processes.

In certain preferred embodiments, the first or the second liquid solventcomprises a flame-resisting or flame-retardant liquid selected from anorganic phosphorus compound, an inorganic phosphorus compound, ahalogenated derivative thereof, or a combination thereof. The organicphosphorus compound or the inorganic phosphorus compound preferably isselected from the group consisting of phosphates, phosphonates,phosphonic acids, phosphorous acids, phosphites, phosphoric acids,phosphinates, phosphines, phosphine oxides, phosphazene compounds,derivatives thereof, and combinations thereof.

In certain embodiments, the first and/or the second liquid solvent isselected from the group consisting of fluorinated ethers, fluorinatedesters, sulfones, sulfides, nitriles, sulfates, siloxanes, silanes,phosphates, phosphonates, phosphinates, phosphines, phosphine oxides,phosphonic acids, phosphorous acid, phosphites, phosphoric acids,phosphazene compounds, derivatives thereof, and combinations thereof.

In some embodiments, the first or the second liquid solvent is selectedfrom a phosphate, phosphonate, phosphinate, phosphine, or phosphineoxide having the structure of:

wherein R¹⁰, R¹¹, and R¹², are independently selected from the groupconsisting of alkyl, aryl, heteroalkyl, heteroaryl, halogen substitutedalkyl, halogen substituted aryl, halogen substituted heteroalkyl,halogen substituted heteroaryl, alkoxy, aryloxy, heteroalkoxy,heteroaryloxy. halogen substituted alkoxy, halogen substituted aryloxy,halogen substituted heteroalkoxy, and halogen substituted heteroaryloxyfunctional groups, and the second liquid solvent is stable under anapplied electrical potential no less than 4 V.

In some embodiments, the first or the second liquid solvent comprises aphosphoranamine having the structure of:

wherein R¹, R², and R³ ae independently selected from the groupconsisting of alkyl, aryl, heteroalkyl, heteroaryl, halogen substitutedalkyl, halogen substituted aryl, halogen substituted heteroalkyl,halogen substituted heteroaryl, alkoxy, aryloxy, heteroalkoxy,heteroaryloxy, halogen substituted alkoxy, halogen substituted aryloxy,halogen substituted heteroalkoxy, and halogen substituted heteroaryloxyfunctional groups, wherein R¹, R², and R³ are represented by at leasttwo different substituents and wherein X is selected from the groupconsisting of an organosiylyl group or a tert-butyl group. The R¹, R²,and R³ may be each independently selected from the group consisting ofan alkoxy group, and an aryloxy group.

The polymer electrolyte typically has a lithium ion conductivitytypically from 10⁻⁸ S/cm to 10⁻² S/cm at room temperature. The cathodemay contain a cathode active material (along with an optional conductiveadditive and an optional resin binder) and an optional cathode currentcollector (such as Al foil) supporting the cathode active material. Theanode may have an anode current collector, with or without an anodeactive material in the beginning when the cell is made. It may be notedthat if no conventional anode active material, such as graphite, Si,SiO, Sn, and conversion-type anode materials, and no lithium metal ispresent in the cell when the cell is made and before the cell begins tocharge and discharge, the battery cell is commonly referred to as an“anode-less” lithium cell.

It may be noted that these first liquid solvents, upon polymerization,become essentially non-flammable. These liquid solvents were typicallyknown to be useful for dissolving a lithium salt and not known for theirpolymerizability or their potential as an electrolyte polymer.

In some preferred embodiments, the battery cell contains substantiallyno volatile liquid solvent therein after polymerization. However, it isessential to initially include a liquid solvent in the cell, enablingthe lithium salt to get dissociated into lithium ions and anions. Amajority (>50%, preferably >70%) or substantially all of the liquidsolvent (particularly the organic solvent) is then cured just before orafter curing of the reactive additive. With substantially 0% liquidsolvent, the resulting electrolyte is a solid-state electrolyte. Withless than 30% liquid solvent, we have a quasi-solid electrolyte. Bothare highly flame-resistant.

In certain embodiments, the hybrid electrolyte exhibits a vapor pressureless than 0.001 kPa when measured at 20° C., a vapor pressure less than60% of the vapor pressure of the combined first liquid solvent andlithium salt alone prior to polymerization, a flash point at least 100degrees Celsius higher than a flash point of the liquid solvent prior topolymerization, a flash point higher than 200° C., or no measurableflash point and wherein the polymer has a lithium ion conductivity from10⁻⁸ S/cm to 10⁻² S/cm at room temperature.

A lower proportion of the unpolymerized liquid solvent in theelectrolyte leads to a significantly reduced vapor pressure andincreased flash point or completely eliminated flash point(un-detectable). Although typically by reducing the liquid solventproportion one tends to observe a reduced lithium ion conductivity forthe resulting electrolyte; however, quite surprisingly, after athreshold liquid solvent fraction, this trend is diminished or reversed(the lithium ion conductivity can actually increase with reduced liquidsolvent in some cases).

In certain embodiments, the reactive additive comprises a firstpolymerizable liquid solvent and a second liquid solvent and wherein thesecond liquid solvent either is not polymerizable or is polymerizablebut polymerized to a lesser extent as compared to the firstpolymerizable liquid solvent. The presence of this second liquid solventis designed to impart certain desired properties to the polymerizedelectrolyte, such as lithium ion conductivity, flame retardancy, abilityof the electrolyte to permeate into the electrode (anode and/or cathode)to properly wet the surfaces of the anode active material and/or thecathode active material.

In some embodiments, the second liquid solvent is selected from afluorinated carbonate, hydrofluoroether, fluorinated ester, sulfone,nitrile, phosphate, phosphite, alkyl phosphonate, phosphazene, sulfate,siloxane, silane, 1,3-dioxolane (DOL), 1,2-dimethoxyethane (DME),tetraethylene glycol dimethylether (TEGDME), poly(ethylene glycol)dimethyl ether (PEGDME), diethylene glycol dibutyl ether (DEGDBE),2-ethoxyethyl ether (EEE), sulfone, sulfolane, ethylene carbonate (EC),dimethyl carbonate (DMC), methylethyl carbonate (MEC), diethyl carbonate(DEC), ethyl propionate, methyl propionate, propylene carbonate (PC),gamma.-butyrolactone (γ-BL), acetonitrile (AN), ethyl acetate (EA),propyl formate (PF), methyl formate (MF), toluene, xylene, methylacetate (MA), fluoroethylene carbonate (FEC), vinylene carbonate (VC),allyl ethyl carbonate (AEC), or a combination thereof.

Desirable polymerizable liquid solvents can include fluorinated monomershaving unsaturation (double bonds or triple bonds) in the backbone orcyclic structure (e.g., fluorinated vinyl carbonates, fluorinated vinylmonomers, fluorinated esters, fluorinated vinyl esters, and fluorinatedvinyl ethers). These chemical species may also be used as a secondliquid solvent in the presently disclosed electrolyte. Fluorinated vinylesters include R_(f)CO₂CH═CH₂ and Propenyl Ketones, R_(f)COCH═CHCH₃,where Rr is F or any F-containing functional group (e.g., CF₂— andCF₂CF₃—).

Two examples of fluorinated vinyl carbonates are given below:

These liquid solvents, as a monomer, can be cured in the presence of aninitiator (e.g., 2-Hydroxy-2-methyl-1-phenyl-propan-1-one, CibaDAROCUR-1173, which can be activated by UV or electron beam):

In some embodiments, the fluorinated carbonate is selected from vinyl-or double bond-containing variants of fluoroethylene carbonate (FEC),DFDMEC, FNPEC, hydrofluoro ether (HFE), trifluoro propylene carbonate(FPC), or methyl nonafluorobutyl ether (MFE), wherein the chemicalformulae for FEC, DFDMEC, and FNPEC, respectively are shown below:

Desirable sulfones as a polymerizable first liquid solvent or as asecond liquid solvent include, but not limited to, alkyl and aryl vinylsulfones or sulfides; e.g., ethyl vinyl sulfide, allyl methyl sulfide,phenyl vinyl sulfide, phenyl vinyl sulfoxide, ethyl vinyl sulfone, allylphenyl sulfone, allyl methyl sulfone, and divinyl sulfone.

Simple alkyl vinyl sulfones, such as ethyl vinyl sulfone, may bepolymerized via emulsion and bulk methods. Propyl vinyl sulfone may bepolymerized by alkaline persulfate initiators to form soft polymers. Itmay be noted that aryl vinyl sulfone, e.g., naphthyl vinyl sulfone,phenyl vinyl sulfone, and parra-substituted phenyl vinyl sulfone (R=NH₂,NO₂ or Br), were reported to be unpolymerizable with free-radicalinitiators. However, we have observed that phenyl and methyl vinylsulfones can be polymerized with several anionic-type initiators.Effective anionic-type catalysts or initiators are n-BuLi, ZnEt2,LiN(CH₂)₂, NaNH₂, and complexes of n-LiBu with ZnEt2 or AlEh. A secondsolvent, such as pyridine, sulfolane, toluene or benzene, can be used todissolve alkyl vinyl sulfones, aryl vinyl sulfones, and other largersulfone molecules.

In certain embodiments, the sulfone is selected from TrMS, MTrMS, TMS,or vinyl or double bond-containing variants of TrMS, MTrMS, TMS, EMS,MMES, EMES, EMEES, or a combination thereof; their chemical formulaebeing given below:

The cyclic structure, such as TrMS, MTrMS, and TMS, can be polymerizedvia ring-opening polymerization with the assistance of an ionic typeinitiator.

The nitrile may be selected from AND, GLN, SEN, or a combination thereofand their chemical formulae are given below:

In some embodiments, the phosphate (including various derivatives ofphosphoric acid), alkyl phosphonate, phosphazene, phosphite, or sulfateis selected from tris(trimethylsilyl) phosphite (TTSPi), alkylphosphate, triallyl phosphate (TAP), ethylene sulfate (DTD), acombination thereof, or a combination with 1,3-propane sultone (PS) orpropene sultone (PES). The phosphate, alkyl phosphonate, or phosphazenemay be selected from the following:

wherein R=H, NH₂, or C₁-C₆ alkyl.

Phosphonate moieties can be readily introduced into vinyl monomers toproduce allyl-type, vinyl-type, styrenic-type and (meth)acrylic-typemonomers bearing phosphonate groups (e.g., either mono orbisphosphonate). These liquid solvents may serve as a first or a secondliquid solvent in the electrolyte composition. The phosphate, alkylphosphonate, phosphonic acid, and phosphazene, upon polymerization, arefound to be essentially non-flammable. Good examples include diethylvinylphosphonate dimethyl vinylphosphonate, vinylphosphonic acid,diethyl allyl phosphate, and diethyl allylphosphonate:

Examples of initiator compounds that can be used in the polymerizationof vinylphosphonic acid are peroxides such as benzoyl peroxide, toluylperoxide, di-tert.butyl peroxide, chloro benzoyl peroxide, orhydroperoxides such as methylethyl ketone peroxide, tert, butylhydroperoxide, cumene hydroperoxide, hydrogen Superoxide, orazo-bis-iso-butyro nitrile, or sulfinic acids such asp-methoxyphenyl-sulfinic acid, isoamyl-sulfinic acid, benzene-sulfinicacid, or combinations of various of such catalysts with one anotherand/or combinations for example, with formaldehyde sodium sulfoxylate orwith alkali metal sulfites.

The siloxane or silane may be selected from alkylsiloxane (Si—O),alkyylsilane (Si—C), liquid oligomeric silaxane (—Si—O—Si—), or acombination thereof.

The reactive additive may further comprise an amide group selected fromN,N-dimethylacetamide, N,N-diethylacetamide, N,N-dimethylformamide,N,N-diethylformamide, or a combination thereof.

In certain embodiments, the crosslinking agent comprises a compoundhaving at least one reactive group selected from a hydroxyl group, anamino group, an imino group, an amide group, an acrylic amide group, anamine group, an acrylic group, an acrylic ester group, or a mercaptogroup in the molecule.

In certain embodiments, the crosslinking agent is selected frompoly(diethanol) diacrylate, poly(ethyleneglycol)dimethacrylate,poly(diethanol) dimethylacrylate, poly(ethylene glycol) diacrylate,lithium hexafluorophosphate (LiPF₆), lithium borofluoride (LiBF₄),lithium hexafluoroarsenide (LiAsF₆), lithium trifluoro-metasulfonate(LiCF₃SO₃), bis-trifluoromethyl sulfonylimide lithium (LiN(CF₃SO₂)₂),lithium bis(oxalato)borate (LiBOB), lithium oxalyldifluoroborate(LiBF₂C₂O₄), lithium oxalyldifluoroborate (LiBF₂C₂O₄), or a combinationthereof.

The initiator may be selected from an azo compound (e.g.,azodiisobutyronitrile, AIBN), azobisisobutyronitrile,azobisisoheptonitrile, dimethyl azobisisobutyrate, benzoyl peroxidetert-butyl peroxide and methyl ethyl ketone peroxide, benzoyl peroxide(BPO), bis(4-tert-butylcyclohexyl)peroxydicarbonate, t-amylperoxypivalate, 2,2′-azobis-(2,4-dimethylvaleronitrile),2,2′-azobis-(2-methylbutyronitrile),1,1-azobis(cyclohexane-1-carbonitrile, benzoylperoxide (BPO), hydrogenperoxide, dodecamoyl peroxide, isobutyryl peroxide, cumenehydroperoxide, tert-butyl peroxypivalate, diisopropyl peroxydicarbonate,or a combination thereof.

In the disclosed polymer electrolyte, the lithium salt may be selectedfrom lithium perchlorate (LiClO₄), lithium hexafluorophosphate (LiPF₆),lithium borofluoride (LiBF₄), lithium hexafluoroarsenide (LiAsF₆),lithium trifluoro-metasulfonate (LiCF₃SO₃), bis-trifluoromethylsulfonylimide lithium (LiN(CF₃SO₂)₂), lithium bis(oxalato)borate(LiBOB), lithium oxalyldifluoroborate (LiBF₂C₂O₄), lithiumoxalyldifluoroborate (LiBF₂C₂O₄), lithium nitrate (LiNO₃),Li-Fluoroalkyl-Phosphates (LiPF₃(CF₂CF₃)₃), lithiumbisperfluoro-ethysulfonylimide (LiBETI), lithiumbis(trifluoromethanesulphonyl)imide, lithium bis(fluorosulphonyl)imide,lithium trifluoromethanesulfonimide (LiTFSI), an ionic liquid lithiumsalt, or a combination thereof.

The crosslinking agent preferably comprises a compound having at leastone reactive group selected from a hydroxyl group, an amino group, animino group, an amide group, an amine group, an acrylic group, or amercapto group in the molecule. The amine group is preferably selectedfrom Chemical Formula 2:

In the rechargeable lithium battery, the reactive additive may furthercomprise a chemical species represented by Chemical Formula 3 or aderivative thereof and the crosslinking agent comprises a chemicalspecies represented by Chemical Formula 4 or a derivative thereof:

where R₁ is hydrogen or methyl group, and R₂ and R₃ are eachindependently one selected from the group consisting of hydrogen,methyl, ethyl, propyl, diallylaminopropyl (—C₃ H₆ N(R′)₂) andhydroxyethyl (CH₂ CH₂ OH) groups, and R₄ and R₅ are each independentlyhydrogen or methyl group, and n is an integer from 3 to 30, wherein R′is C₁-C₅ alkyl group.

Examples of suitable vinyl monomers having Chemical formula 3 includeacrylamide, N,N-dimethylacrylamide, N,N-diethylacrylamide,N-isopropylacrylamide, N,N-dimethylamino-propylacrylamide, andN-acryloylmorpholine. Among these species, N-isopropylacrylamide andN-acryloylmorpholine are preferred.

The crosslinking agent is preferably selected from N,N-methylenebisacrylamide, epichlorohydrin, 1,4-butanediol diglycidyl ether,tetrabutylammonium hydroxide, cinnamic acid, ferric chloride, aluminumsulfate octadecahydrate, diepoxy, dicarboxylic acid compound,poly(potassium 1-hydroxy acrylate) (PKHA), glycerol diglycidyl ether(GDE), ethylene glycol, polyethylene glycol, polyethylene glycoldiglycidyl ether (PEGDE), citric acid (Formula 4 below), acrylic acid,methacrylic acid, a derivative compound of acrylic acid, a derivativecompound of methacrylic acid (e.g. polyhydroxyethylmethacrylate),glycidyl functions, N,N′-Methylenebisacrylamide (MBAAm), Ethylene glycoldimethacrylate (EGDMAAm), isobornyl methacrylate, poly (acrylic acid)(PAA), methyl methacrylate, isobornyl acrylate, ethyl methacrylate,isobutyl methacrylate, n-Butyl methacrylate, ethyl acrylate, 2-Ethylhexyl acrylate, n-Butyl acrylate, a diisocyanate (e.g. methylenediphenyl diisocyanate, MDI), an urethane chain, a chemical derivativethereof, or a combination thereof.

The polymer in the electrolyte may form a mixture, copolymer,semi-interpenetrating network, or simultaneous interpenetrating networkwith a second polymer selected from poly(ethylene oxide), polypropyleneoxide, poly(ethylene glycol), poly(acrylonitrile), poly(methylmethacrylate), poly(vinylidene fluoride), poly bis-methoxyethoxyethoxide-phosphazenex, polyvinyl chloride, polydimethylsiloxane,poly(vinylidene fluoride)-hexafluoropropylene, cyanoethyl poly(vinylalcohol), a pentaerythritol tetraacrylate-based polymer, an aliphaticpolycarbonate, a single Li-ion conducting solid polymer electrolyte witha carboxylate anion, a sulfonylimide anion, or sulfonate anion, acrosslinked electrolyte of poly(ethylene glycol) diacrylate orpoly(ethylene glycol) methyl ether acrylate, a sulfonated derivativethereof, or a combination thereof. One or more of these polymers may bepre-mixed into the anode and/or the cathode prior to assembling theelectrodes and other components into a dry cell.

These solid electrolyte particles dispersed in an electrolyte polymercan help enhance the lithium ion conductivity of certain polymers havingan intrinsically low ion conductivity. Preferably and typically, thepolymer has a lithium ion conductivity no less than 10⁻⁵ S/cm, morepreferably no less than 10⁻⁴ S/cm, and further preferably no less than10⁻³ S/cm.

The disclosed lithium battery can be a lithium-ion battery or a lithiummetal battery, the latter having lithium metal as the primary anodeactive material. The lithium metal battery can have lithium metalimplemented at the anode when the cell is made. Alternatively, thelithium may be stored in the cathode active material and the anode sideis lithium metal-free initially. This is called an anode-less lithiummetal battery.

As illustrated in FIG. 2(A), the anode-less lithium cell is in anas-manufactured or fully discharged state according to certainembodiments of the present disclosure. The cell comprises an anodecurrent collector 12 (e.g., Cu foil), a separator, a cathode layer 16comprising a cathode active material, an optional conductive additive(not shown), an optional resin binder (not shown), and an electrolyte(dispersed in the entire cathode layer and in contact with the cathodeactive material), and a cathode current collector 18 that supports thecathode layer 16. There is no lithium metal in the anode side when thecell is manufactured.

In a charged state, as illustrated in FIG. 2(B), the cell comprises ananode current collector 12, lithium metal 20 plated on a surface (or twosurfaces) of the anode current collector 12 (e.g., Cu foil), a separator15, a cathode layer 16, and a cathode current collector 18 supportingthe cathode layer. The lithium metal comes from the cathode activematerial (e.g., LiCoO₂ and LiMn₂O₄) that contains Li element when thecathode is made. During a charging step, lithium ions are released fromthe cathode active material and move to the anode side to deposit onto asurface or both surfaces of an anode current collector.

One unique feature of the presently disclosed anode-less lithium cell isthe notion that there is substantially no anode active material and nolithium metal is present when the battery cell is made. The commonlyused anode active material, such as an intercalation type anode material(e.g., graphite, carbon particles, Si, SiO, Sn, SnO₂, Ge, etc.), P, orany conversion-type anode material, is not included in the cell. Theanode only contains a current collector or a protected currentcollector. No lithium metal (e.g., Li particle, surface-stabilized Liparticle, Li foil, Li chip, etc.) is present in the anode when the cellis made; lithium is basically stored in the cathode (e.g., Li element inLiCoO₂, LiMn₂O₄, lithium iron phosphate, lithium polysulfides, lithiumpolyselenides, etc.). During the first charge procedure after the cellis sealed in a housing (e.g., a stainless steel hollow cylinder or anAl/plastic laminated envelop), lithium ions are released from theseLi-containing compounds (cathode active materials) in the cathode,travel through the electrolyte/separator into the anode side, and getdeposited on the surfaces of an anode current collector. During asubsequent discharge procedure, lithium ions leave these surfaces andtravel back to the cathode, intercalating or inserting into the cathodeactive material.

Such an anode-less cell is much simpler and more cost-effective toproduce since there is no need to have a layer of anode active material(e.g., graphite particles, along with a conductive additive and abinder) pre-coated on the Cu foil surfaces via the conventional slurrycoating and drying procedures. The anode materials and anode activelayer manufacturing costs can be saved. Furthermore, since there is noanode active material layer (otherwise typically 40-200 μm thick), theweight and volume of the cell can be significantly reduced, therebyincreasing the gravimetric and volumetric energy density of the cell.

Another important advantage of the anode-less cell is the notion thatthere is no lithium metal in the anode when a lithium metal cell ismade. Lithium metal (e.g., Li metal foil and particles) is highlysensitive to air moisture and oxygen and notoriously known for itsdifficulty and danger to handle during manufacturing of a Li metal cell.The manufacturing facilities must be equipped with special class of dryrooms, which are expensive and significantly increase the battery cellcosts.

The anode current collector may be selected from a foil, perforatedsheet, or foam of Cu, Ni, stainless steel, Al, graphene, graphite,graphene-coated metal, graphite-coated metal, carbon-coated metal, or acombination thereof. Preferably, the current collector is a Cu foil, Nifoil, stainless steel foil, graphene-coated Al foil, graphite-coated Alfoil, or carbon-coated Al foil.

The anode current collector typically has two primary surfaces.Preferably, one or both of these primary surfaces is deposited withmultiple particles or coating of a lithium-attracting metal(lithiophilic metal), wherein the lithium-attracting metal, preferablyhaving a diameter or thickness from 1 nm to 10 μm, is selected from Au,Ag, Mg, Zn, Ti, K, Al, Fe, Mn, Co, Ni, Sn, V, Cr, an alloy thereof, or acombination thereof. This deposited metal layer may be further depositedwith a layer of graphene that covers and protects the multiple particlesor coating of the lithiophilic metal.

The graphene layer may comprise graphene sheets selected fromsingle-layer or few-layer graphene, wherein the few-layer graphenesheets are commonly defined to have 2-10 layers of stacked grapheneplanes having an inter-plane spacing d₀₀₂ from 0.3354 nm to 0.6 nm asmeasured by X-ray diffraction. The single-layer or few-layer graphenesheets may contain a pristine graphene material having essentially zero% of non-carbon elements, or a non-pristine graphene material having0.001% to 45% by weight of non-carbon elements. The non-pristinegraphene may be selected from graphene oxide, reduced graphene oxide,graphene fluoride, graphene chloride, graphene bromide, graphene iodide,hydrogenated graphene, nitrogenated graphene, doped graphene, chemicallyfunctionalized graphene, or a combination thereof.

The graphene layer may comprise graphene balls and/or graphene foam.Preferably, the graphene layer has a thickness from 1 nm to 50 μm and/orhas a specific surface area from 5 to 1000 m²/g (more preferably from 10to 500 m²/g).

For a lithium-ion battery featuring the presently disclosed electrolyte,there is no particular restriction on the selection of an anode activematerial. The anode active material may be selected from the groupconsisting of: (a) silicon (Si), germanium (Ge), tin (Sn), lead (Pb),antimony (Sb), phosphorus (P), bismuth (Bi), zinc (Zn), aluminum (Al),titanium (Ti), nickel (Ni), cobalt (Co), and cadmium (Cd); (b) alloys orintermetallic compounds of Si, Ge, Sn, Pb, Sb, Bi, Zn, Al, Ti, Ni, Co,or Cd with other elements; (c) oxides, carbides, nitrides, sulfides,phosphides, selenides, and tellurides of Si, Ge, Sn, Pb, Sb, Bi, Zn, Al,Ti, Fe, Ni, Co, V, or Cd, and their mixtures, composites, orlithium-containing composites; (d) salts and hydroxides of Sn; (e)lithium titanate, lithium manganate, lithium aluminate, lithium titaniumniobate, lithium-containing titanium oxide, lithium transition metaloxide, ZnCo₂O₄; (f) carbon or graphite particles (g) prelithiatedversions thereof; and (h) combinations thereof.

Another surprising and of tremendous scientific and technologicalsignificance is our discovery that the flammability of any volatileorganic solvent can be effectively suppressed provided that asufficiently high amount of a lithium salt is added and dissolved inthis organic solvent and/or a sufficient amount of liquid solvent ispolymerized to form a solid-like or quasi-solid electrolyte (e.g., firstelectrolyte in the cathode). In general, such a quasi-solid electrolyteexhibits a vapor pressure less than 0.01 kPa and often less than 0.001kPa (when measured at 20° C.) and less than 0.1 kPa and often less than0.01 kPa (when measured at 100° C.). (The vapor pressures of thecorresponding neat solvent, without any lithium salt dissolved therein,are typically significantly higher.) In many cases, the vapor moleculesare practically too few to be detected.

A highly significant observation is that the polymer derived(polymerized) from an otherwise volatile solvent (monomer) candramatically curtail the amount of volatile solvent molecules that canescape into the vapor phase in a thermodynamic equilibrium condition. Inmany cases, this has effectively prevented any flammable gas moleculesfrom initiating a flame even at an extremely high temperature. The flashpoint of the quasi-solid or solid-state electrolyte is typically atleast 100 degrees (often >150 degrees) higher than the flash point ofthe neat organic solvent without polymerization. In most of the cases,either the flash point is significantly higher than 200° C. or no flashpoint can be detected. The electrolyte just would not catch on fire.Furthermore, any accidentally initiated flame does not sustain forlonger than 3 seconds. This is a highly significant discovery,considering the notion that fire and explosion concern has been a majorimpediment to widespread acceptance of battery-powered electricvehicles. This new technology could significantly impact the emergenceof a vibrant EV industry.

In addition to the non-flammability and high lithium ion transferencenumbers, there are several additional benefits associated with using thepresently disclosed quasi-solid or solid-state electrolytes. As oneexample, these electrolytes can significantly enhance cycling and safetyperformance of rechargeable lithium batteries through effectivesuppression of lithium dendrite growth. Due to a good contact betweenthe electrolyte and an electrode, the interfacial impedance can besignificantly reduced. Additionally, the local high viscosity induced bypresence of a polymer in the anode can increase the pressure from theelectrolyte to inhibit dendrite growth, potentially resulting in a moreuniform deposition of lithium ions on the surface of the anode. The highviscosity could also limit anion convection near the deposition area,promoting more uniform deposition of Li ions. These reasons, separatelyor in combination, are believed to be responsible for the notion that nodendrite-like feature has been observed with any of the large number ofrechargeable lithium cells that we have investigated thus far.

As another benefit example, this electrolyte is capable of inhibitinglithium polysulfide dissolution at the cathode and migration to theanode of a Li—S cell, thus overcoming the polysulfide shuttle phenomenonand allowing the cell capacity not to decay significantly with time.Consequently, a coulombic efficiency nearing 100% along with long cyclelife can be achieved. When a concentrated electrolyte or crosslinkedpolymer is used, the solubility of lithium polysulfide will be reducedsignificantly.

The lithium salt may be selected from lithium perchlorate (LiClO₄),lithium hexafluorophosphate (LiPF₆), lithium borofluoride (LiBF₄),lithium hexafluoroarsenide (LiAsF₆), lithium trifluoro-metasulfonate(LiCF₃SO₃), bis-trifluoromethyl sulfonylimide lithium (LiN(CF₃SO₂)₂),lithium bis(oxalato)borate (LiBOB), lithium oxalyldifluoroborate(LiBF₂C₂O₄), lithium oxalyldifluoroborate (LiBF₂C₂O₄), lithium nitrate(LiNO₃), Li-Fluoroalkyl-Phosphates (LiPF₃(CF₂CF₃)₃), lithiumbisperfluoro-ethysulfonylimide (LiBETI), lithiumbis(trifluoromethanesulphonyl)imide, lithium bis(fluorosulphonyl)imide,lithium trifluoromethanesulfonimide (LiTFSI), an ionic liquid lithiumsalt, or a combination thereof.

There is also no restriction on the type of the cathode materials thatcan be used in practicing the present disclosure. For Li—S cells, thecathode active material may contain lithium polysulfide or sulfur. Ifthe cathode active material includes lithium-containing species (e.g.,lithium polysulfide) when the cell is made, there is no need to have alithium metal pre-implemented in the anode.

There are no particular restrictions on the types of cathode activematerials that can be used in the presently disclosed lithium battery,which can be a primary battery or a secondary battery. The rechargeablelithium metal or lithium-ion cell may preferably contain a cathodeactive material selected from, as examples, a layered compound LiMO₂,spinel compound LiM₂O₄, olivine compound LiMPO₄, silicate compoundLi₂MSiO₄, Tavorite compound LiMPO₄F, borate compound LiMBO₃, or acombination thereof, wherein M is a transition metal or a mixture ofmultiple transition metals.

In a rechargeable lithium cell, the cathode active material may beselected from a metal oxide, a metal oxide-free inorganic material, anorganic material, a polymeric material, sulfur, lithium polysulfide,selenium, or a combination thereof. The metal oxide-free inorganicmaterial may be selected from a transition metal fluoride, a transitionmetal chloride, a transition metal dichalcogenide, a transition metaltrichalcogenide, or a combination thereof. In a particularly usefulembodiment, the cathode active material is selected from FeF₃, FeCl₃,CuCl₂, TiS₂, TaS₂, MoS₂, NbSe₃, MnO₂, CoO₂, an iron oxide, a vanadiumoxide, or a combination thereof, if the anode contains lithium metal asthe anode active material. The vanadium oxide may be preferably selectedfrom the group consisting of VO₂, Li_(x)VO₂, V₂O₅, Li_(x)V₂O₅, V₃O₈,Li_(x)V₃O₅, Li_(x)V₃O₇, V₄O₉, Li_(x)V₄O₉, V₆O₁₃, Li_(x)V₆O₁₃, theirdoped versions, their derivatives, and combinations thereof, wherein0.1<x<5. For those cathode active materials containing no Li elementtherein, there must be a lithium source implemented in the cathode sideto begin with. This can be any compound that contains a high lithiumcontent, or a lithium metal alloy, etc.

In a rechargeable lithium cell (e.g., the lithium-ion battery cell), thecathode active material may be selected to contain a layered compoundLiMO₂, spinel compound LiM₂O₄, olivine compound LiMPO₄, silicatecompound Li₂MSiO₄, Tavorite compound LiMPO₄F, borate compound LiMBO₃, ora combination thereof, wherein M is a transition metal or a mixture ofmultiple transition metals.

Particularly desirable cathode active materials comprise lithium nickelmanganese oxide (LiNi_(a)Mn_(2−a)O₄, 0<a<2), lithium nickel manganesecobalt oxide (LiNi_(n)Mn_(m)Co_(1−n−m)O₂, 0<n<1, 0<m<1, n+m<1), lithiumnickel cobalt aluminum oxide (LiNi_(c)Co Al_(1−c−d)O₂, 0<c<1, 0<d<1,c+d<1), lithium manganate (LiMn₂O₄), lithium iron phosphate (LiFePO₄),lithium manganese oxide (LiMnO₂), lithium cobalt oxide (LiCoO₂), lithiumnickel cobalt oxide (LiNi_(p)Co_(1−p)O₂, 0<p<1), or lithium nickelmanganese oxide (LiNi_(q)Mn_(2−q)O₄, 0<q<2).

In a preferred lithium metal secondary cell, the cathode active materialpreferably contains an inorganic material selected from: (a) bismuthselenide or bismuth telluride, (b) transition metal dichalcogenide ortrichalcogenide, (c) sulfide, selenide, or telluride of niobium,zirconium, molybdenum, hafnium, tantalum, tungsten, titanium, cobalt,manganese, iron, nickel, or a transition metal; (d) boron nitride, or(e) a combination thereof. Again, for those cathode active materialscontaining no Li element therein, there must be a lithium sourceimplemented in the cathode side to begin with.

In another preferred rechargeable lithium cell (e.g. a lithium metalsecondary cell or a lithium-ion cell), the cathode active materialcontains an organic material or polymeric material selected fromPoly(anthraquinonyl sulfide) (PAQS), lithium oxocarbons (includingsquarate, croconate, and rhodizonate lithium salts), oxacarbon(including quinines, acid anhydride, and nitrocompound),3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA),poly(anthraquinonyl sulfide), pyrene-4,5,9,10-tetraone (PYT),polymer-bound PYT, Quino(triazene), redox-active organic material(redox-active structures based on multiple adjacent carbonyl groups(e.g., “C₆O₆”-type structure, oxocarbons), Tetracyanoquinodimethane(TCNQ), tetracyanoethylene (TCNE), 2,3,6,7,10,11-hexamethoxytriphenylene(HMTP), poly(5-amino-1,4-dyhydroxy anthraquinone) (PADAQ), phosphazenedisulfide polymer ([(NPS₂)₃]n), lithiated 1,4,5,8-naphthalenetetraolformaldehyde polymer, Hexaazatrinaphtylene (HATN), Hexaazatriphenylenehexacarbonitrile (HAT(CN)6), 5-Benzylidene hydantoin, Isatine lithiumsalt, Pyromellitic diimide lithium salt, tetrahydroxy-p-benzoquinonederivatives (THQLi₄), N,N′-diphenyl-2,3,5,6-tetraketopiperazine (PHP),N,N′-diallyl-2,3,5,6-tetraketopiperazine (AP),N,N′-dipropyl-2,3,5,6-tetraketopiperazine (PRP), a thioether polymer, aquinone compound, 1,4-benzoquinone, 5,7,12,14-pentacenetetrone (PT),5-amino-2,3-dihydro-1,4-dyhydroxy anthraquinone (ADDAQ),5-amino-1,4-dyhydroxy anthraquinone (ADAQ), calixquinone, Li₄C₆O₆,Li₂C₆O₆, Li₆C₆O₆, or a combination thereof.

The thioether polymer may be selected fromPoly[methanetetryl-tetra(thiomethylene)](PMTTM),Poly(2,4-dithiopentanylene) (PDTP), or Poly(ethene-1,1,2,2-tetrathiol)(PETT) as a main-chain thioether polymer, in which sulfur atoms linkcarbon atoms to form a polymeric backbones. The side-chain thioetherpolymers have polymeric main-chains that consist of conjugating aromaticmoieties, but having thioether side chains as pendants. Among themPoly(2-phenyl-1,3-dithiolane) (PPDT),Poly(1,4-di(1,3-dithiolan-2-yl)benzene) (PDDTB),poly(tetrahydrobenzodithiophene) (PTHBDT), andpoly[1,2,4,5-tetrakis(propylthio)benzene](PTKPTB) have a polyphenylenemain chain, linking thiolane on benzene moieties as pendants. Similarly,poly[3,4(ethylenedithio)thiophene] (PEDTT) has polythiophene backbone,linking cyclo-thiolane on the 3,4-position of the thiophene ring.

In yet another preferred rechargeable lithium cell, the cathode activematerial contains a phthalocyanine compound selected from copperphthalocyanine, zinc phthalocyanine, tin phthalocyanine, ironphthalocyanine, lead phthalocyanine, nickel phthalocyanine, vanadylphthalocyanine, fluorochromium phthalocyanine, magnesium phthalocyanine,manganous phthalocyanine, dilithium phthalocyanine, aluminumphthalocyanine chloride, cadmium phthalocyanine, chlorogalliumphthalocyanine, cobalt phthalocyanine, silver phthalocyanine, ametal-free phthalocyanine, a chemical derivative thereof, or acombination thereof. This class of lithium secondary batteries has ahigh capacity and high energy density. Again, for those cathode activematerials containing no Li element therein, there must be a lithiumsource implemented in the cathode side to begin with.

As illustrated in FIG. 1(B), the present disclosure also provides anelectrolyte composition comprising: (a) a first solution, comprising atleast a polymerizable first liquid solvent; and (b) a second solution,comprising an initiator and/or crosslinking agent, a lithium salt, and asecond non-aqueous liquid solvent (e.g., an organic solvent or ionicliquid solvent); wherein the first solution and the second solution arestored separately before the first solution and the second solution aremixed to form the electrolyte. The first liquid solvent has a lowerflash point (higher flammability), a higher vapor pressure, a higherdielectric constant, or a higher solubility of the lithium salt ascompared with the second liquid solvent. Actually, the lithium salt maybe dissolved in the first solvent, the second solvent, or both.Alternatively, the initiator and/or crosslinking agent may be directlyadded into the first liquid solvent if no second liquid solvent is used.

The disclosure further provides a method of producing a rechargeablelithium cell (as illustrated in FIG. 1(A)), the method comprising: (a)providing a cathode; (b) providing an anode; (c) combining the cathodeand the anode to form a dry cell; and (d) introducing (e.g., injecting)the presently disclosed electrolyte composition into the dry cell andpolymerizing and/or crosslinking the reactive additive to produce thesubstantially solid-state rechargeable lithium cell. Step (d) maycomprise partially or totally removing any un-polymerized liquidsolvent, if so desired.

In this method, step (a) may be selected from any commonly used cathodeproduction process. For instance, the process may include (i) mixingparticles of a cathode active material, a conductive additive, anoptional resin binder, powder particles of a solid inorganicelectrolyte, and an optional flame retardant in a liquid medium (e.g.,an organic solvent, such as NMP) to form a slurry; and (ii) coating theslurry on a cathode current collector (e.g., an Al foil) and removingthe solvent. The anode in step (b) may be produced in a similar manner,but using particles of an anode active material (e.g., particles of Si,SiO, Sn, SnO₂, graphite, and carbon). The liquid medium used in theproduction of an anode may be water or an organic solvent. Step (c) mayentail combining the anode, a porous separator, the cathode, along withtheir respective current collectors, to form a unit cell which isenclosed in a protective housing to form a dry cell.

As illustrated in FIG. 1(C), the disclosure also provides a method ofproducing the disclosed rechargeable lithium cell, the methodcomprising: (A) mixing particles of a cathode active material, powderparticles of an inorganic solid electrolyte, an optional conductiveadditive (typically required in the cathode), an optional binder(optional but not required since, upon polymerization and/orcrosslinking, the reactive additive becomes a binder that bonds thesolid particles in the electrode together), an optional flame retardant,a reactive additive, and a lithium salt to form a cathode, wherein thereactive additive comprises at least one polymerizable or crosslinkablesolvent and a curing agent or initiator; (B) providing an anode; (C)combining the cathode and the anode to form a cell; and (D) polymerizingand/or crosslinking the reactive additive, prior to or after step (C),to produce the rechargeable lithium cell.

In step (A), particles of a cathode active material, an optionalconductive additive, an optional binder, an optional flame retardant, alithium salt, and particles of an inorganic solid electrolyte powder maybe dissolved or dispersed in a reactive additive (containing at least apolymerizable liquid solvent) to form a slurry. The slurry is attachedto or coated on a primary surface or both primary surfaces of a cathodecurrent collector (e.g., Al foil) to form a cathode.

In certain embodiments, step (B) comprises a procedure of mixingparticles of an anode active material, powder particles of an inorganicsolid electrolyte, an optional conductive additive (not required if theanode active material is a carbon or graphite material), an optionalbinder (not required since, upon polymerization and/or crosslinking, thereactive additive becomes a binder that bonds the solid particles in theelectrode together), an optional flame retardant, a reactive additive(the same or different reactive as used in the cathode), and a lithiumsalt to form an anode.

The method further comprises polymerizing and/or crosslinking thereactive additive, prior to or after step (C), to produce therechargeable lithium cell.

In some desired embodiments, step (A) comprises adding particles of aninorganic solid electrolyte powder in the cathode and step (B) comprisesadding particles of an inorganic solid electrolyte powder in the anode.

Illustrated in FIG. 1(D) is yet another embodiment of the presentdisclosure, which is a method of producing the disclosed rechargeablelithium cell. The method comprises: (A) mixing particles of a cathodeactive material, an optional conductive additive (typically required inthe cathode), an optional binder (not required since the reactiveadditive becomes a binder upon polymerization and/or crosslinking), anoptional flame retardant, powder particles of an inorganic solidelectrolyte, and a reactive additive to form a cathode (preferablycontaining at least one cathode active material layer supported on acurrent collector), wherein the reactive additive comprises at least onepolymerizable liquid solvent; (B) providing an anode; (C) combining thecathode, an optional separator, the anode, and a protective housing toform a cell; and (D) injecting a liquid mixture of a lithium salt, aninitiator or crosslinking agent, an optional flame retardant (if in aliquid state) and a second non-aqueous liquid solvent into the cell andpolymerizing and/or crosslinking the reactive additive to produce therechargeable lithium cell. This may be followed by a step of partiallyor totally removing any un-polymerized solvent.

For the production of a lithium-ion cell, step (B) may comprise mixingparticles of an anode material (e.g., Si, SiO, graphite, carbonparticles, etc.), an optional conductive additive, an optional binder,an optional flame retardant, particles of an inorganic solid electrolytepowder, and a reactive additive to form at least one anode active layersupported on an anode current collector (e.g., Cu foil).

The following examples are presented primarily for the purpose ofillustrating the best mode practice of the present disclosure, not to beconstrued as limiting the scope of the present disclosure.

It may be noted that the more desirable and typical lithium ionconductivity of the polymer (without or with some amount of liquidsolvent) herein studied is from 10⁻⁶ S/cm to 5×10⁻² S/cm and that of theinorganic solid electrolyte (ISE) is from 10⁻⁶ S/cm to 2×10⁻² S/cm. TheISE-to-polymer electrolyte volume ratio can be from 1/99 to 99/1, buttypically from 5/95 to 95/5, more typically from 10/90 to 90/10, furthermore typically from 20/80 to 80/20, and most typically from 30/70 to70/30. The goal is to achieve a lithium ion conductivity of theresulting hybrid electrolyte from 10⁻⁵ S/cm to 5×10⁻² S/cm, preferablygreater than 10⁻⁴ S/cm, and more preferably greater than 10⁻³ S/cm.

Example 1: Preparation of Inorganic Solid Electrolyte (ISE) Powder,Lithium Nitride Phosphate Compound (LIPON)

Particles of Li₃PO₄ (average particle size 4 μm) and urea were preparedas raw materials; 5 g each of Li₃PO₄ and urea was weighed and mixed in amortar to obtain a raw material composition. Subsequently, the rawmaterial composition was molded into 1 cm×1 cm×10 cm rod with a moldingmachine, and the obtained rod was put into a glass tube and evacuated.The glass tube was then subjected to heating at 500° C. for 3 hours in atubular furnace to obtain a lithium nitride phosphate compound (LIPON).The compound was ground in a mortar into a powder form. These ISEparticles can be combined with an in situ cured polymer to form a hybridsolid-state or quasi-solid electrolyte in an anode, a cathode, and/or aseparator.

Example 2: Preparation of Solid Electrolyte Powder, Lithium SuperionicConductors with the Li₁₀GeP₂S₁₂ (LGPS)-Type Structure

The starting materials, Li₂S and SiO₂ powders, were milled to obtainfine particles using a ball-milling apparatus. These starting materialswere then mixed together with P₂S₅ in the appropriate molar ratios in anAr-filled glove box. The mixture was then placed in a stainless steelpot, and milled for 90 min using a high-intensity ball mill. Thespecimens were then pressed into pellets, placed into a graphitecrucible, and then sealed at 10 Pa in a carbon-coated quartz tube. Afterbeing heated at a reaction temperature of 1,000° C. for 5 h, the tubewas quenched into ice water. The resulting inorganic solid electrolytematerial was then subjected to grinding in a mortar to form a powdersample to be later added as inorganic solid electrolyte particlesdispersed in an intended polymer electrolyte matrix.

Example 3: Preparation of garnet-type inorganic solid electrolyte powder

The synthesis of the c-Li_(6.25)Al_(0.25)La₃Zr₂O₁₂ was based on amodified sol-gel synthesis-combustion method, resulting insub-micron-sized particles after calcination at a temperature of 650° C.(J. van den Broek, S. Afyon and J. L. M. Rupp, Adv. Energy Mater., 2016,6, 1600736).

For the synthesis of cubic garnet particles of the compositionc-Li_(6.25)Al_(0.25)La₃Zr₂O₁₂, stoichiometric amounts of LiNO₃,Al(NO₃)₃-9H₂O, La(NO₃)₃-6(H₂O), and zirconium (IV) acetylacetonate weredissolved in a water/ethanol mixture at temperatures of 70° C. To avoidpossible Li-loss during calcination and sintering, the lithium precursorwas taken in a slight excess of 10 wt % relative to the otherprecursors. The solvent was left to evaporate overnight at 95° C. toobtain a dry xerogel, which was ground in a mortar and calcined in avertical tube furnace at 650° C. for 15 h in alumina crucibles under aconstant synthetic airflow. Calcination directly yielded the cubic phasec-Li_(6.25)Al_(0.25)La₃Zr₂O₁₂, which was ground to a fine powder in amortar for further processing.

The c-Li_(6.25)Al_(0.25)La₃Zr₂O₁₂ solid electrolyte pellets withrelative densities of ˜87±3% made from this powder (sintered in ahorizontal tube furnace at 1070° C. for 10 h under O₂ atmosphere)exhibited an ionic conductivity of ˜0.5×10⁻³ S cm⁻¹ (RT). Thegarnet-type solid electrolyte with a composition ofc-Li_(6.25)Al_(0.25)La₃Zr₂O₁₂ (LLZO) in a powder form was dispersed inseveral in situ cured ion-conducting polymers.

Example 4: Preparation of Sodium Superionic Conductor (NASICON) TypeInorganic Solid Electrolyte Powder

The Na_(3.1)Zr_(1.95)M_(0.05)Si₂PO₁₂ (M=Mg, Ca, Sr, Ba) materials weresynthesized by doping with alkaline earth ions at octahedral6-coordination Zr sites. The procedure employed consists of twosequential steps. Firstly, solid solutions of alkaline earth metaloxides (MO) and ZrO₂ were synthesized by high energy ball milling at 875rpm for 2 h. Then NASICON Na_(3.1)Zr_(1.95)M_(0.05)Si₂PO₁₂ structureswere synthesized through solid-state reaction of Na₂CO₃,Zr_(1.95)M_(0.05)O_(3.95), SiO₂, and NH₄H₂PO₄ at 1260° C.

Example 5: Lithium Metal Cell Containing an In Situ Polymerized VC orFEC as the First Liquid Solvent and TEP as a Second Liquid Solvent

In one example, vinylene carbonate (VC) or fluoroethylene carbonate(FEC) as a first liquid solvent, TEP as a second liquid solvent (flameretardant), and poly(ethylene glycol) diacrylate (PEGDA, as acrosslinking agent) were stirred under the protection of argon gas untila homogeneous solution was obtained. The TEP has the following chemicalstructure:

Subsequently, lithium hexafluoro phosphate, as a lithium salt, was addedand dissolved in the above solution to obtain a reactive mixturesolution, wherein the weight fractions of VC or FEC, TEP, polyethyleneglycol diacrylate, and lithium hexafluoro phosphate were 80 wt %, 5 w %,10 wt %, and 5 wt %, respectively.

A lithium metal cell was made, comprising a lithium metal foil as theanode active material, a cathode (comprising 85% by weight of LiCoO₂ asthe cathode active material, 7% of Li₇La₃Zr₂O₁₂ particles, 5% PVDFbinder, and 3% combined graphene/CNT as a conductive additive), and asolid-state electrolyte-based separator composed of particles ofLi₇La₃Zr₂O₁₂ embedded in a poly(vinylidene fluoride)-hexafluoropropylene(PVDF-HFP) matrix (inorganic solid electrolyte/PVDF-HFP ratio=4/6). Thiscell was then injected with the reactive solution mixture (10% by weightbased on the total cell weight). The cell was then irradiated withelectron beam at room temperature until a total dosage of 40 Gy wasreached. In-situ polymerization of the polymerizable first liquidsolvent in the battery cell was accomplished, resulting in a quasi-solidelectrolyte that permeates into the cathode to wet the surfaces ofLiCoO₂ particles, impregnates the porous separator, and comes in contactwith the lithium metal in the anode.

Example 6: 1,3-Dioxolane (DOL) as the Polymerizable First Solvent and anUnsaturated Phosphazene, Alone or in Combination with EC, as a SecondSolvent

In this study, all of the electrolytes were prepared in an Ar-filledglovebox. The polymerizable liquid electrolyte composition comprisesanhydrous DOL (99.8%, containing approximately 75 ppm butylatedhydroxytoluene (BHT) as inhibitor; Sigma-Aldrich). A total of 0.6 MLiTFSI (TCI America) and 0.4 M LiDFOB (Sigma-Aldrich) were added to theabove solvent to prepare the electrolytes. One electrolyte was preparedby dissolving the salts in pure DOL. In several electrolytes, a ternarysalt composition (0.6 M LiTFSI+0.2 M LiDFOB and 0.2 M LiBOB[Sigma-Aldrich]) was used to prepare the electrolytes using the sameprocess. Aluminum triflate (Al(OTf)3, 99%; Alfa Aesar) with aconcentration of 2 mM was also added to accelerate the polymerizationreaction. Electrolyte compositions used in the study were created bydiluting the homogeneous solutions of DOL-Al(OTf)3 with appropriateamounts of DOL-LITFSI to create initially liquid DOL electrolytescontaining variable fractions of Al(OTf)3. All of the electrolytes wererespectively injected into dry cells to facilitate the polymerization ofDOL. The polymerization typically proceeded at 25-75° C. for 1-48 hours.

The inorganic solid electrolyte was LGPS-type obtained in Example 2 andthe second liquid solvent was an unsaturated phosphazene (UPA) havingthe following structure:

This UPA was synthesized according to a procedure reported by Mason K.Harrup, et al. “Unsaturated phosphazenes as co-solvents for lithium-ionbattery electrolytes,” Journal of Power Sources 278 (2015) 794-801. TheVC/UPA or FEC/UPA ratio was varied as 25/75, 50/50, and 75/25.

Example 7: VC or FEC as the First Liquid Solvent and Trifluoro-Phosphate(TFP) as the Second Liquid Solvent

In this study, VC or FEC was used as the first liquid solvent,azodiisobutyronitrile (AIBN) as the initiator, lithium difluoro(oxalate)borate (LiDFOB) as the lithium salt, and TFP as the secondflame-retardant liquid solvent. TFP has the following chemicalstructure:

Solutions containing 1.5 M LiDFOB in VC and FEC, respectively, and 0.2wt % AIBN (vs VC or FEC) were prepared. Then, TFP (TFPNC or TFP/FECratios being from 10/90 to 50/50) was added into the solution to formmixed electrolyte solutions. The electrolyte solutions were separatelyinjected into different dry battery cells, allowing the electrolytesolution to permeate into the anode (wetting out particles of the ISEobtained in Example 3 and the anode active material; e.g., graphiteparticles), into the cathode (wetting out the ISE and the cathode activematerial; e.g., NCM-532 particles), and into the porous separator layer(porous PE/PP film or nonwoven of electro-spun PAN nano-fibers). Thebattery cells were stored at 60° C. for 24 h and then 80° C. for another2 h to obtain polymerized VC or polymerized FEC that contained TFP intheir matrix of polymer chains. The polymerization scheme of VC is shownbelow (Reaction scheme 1):

It may be noted that presumably FEC inside the cell may be naturallyconverted to VC according to the following reaction and the resulting VCcan be polymerized according to the following Reaction scheme 2:

The resultant VC is then polymerized according to Reaction scheme 1shown above.Presumably, the HF can help form a LiF-rich solid electrolyte interfacelayer on Li anode or graphite anode material surface for improvedcycling performance.

Example 8: Vinyl Ethylene Sulfite (VES) as the First Solvent andHydrofluoro Ether (HFE) as the Second Solvent

Under the protection of an argon gas atmosphere, vinyl ethylene sulfite(VES), hydrofluoro ether (FIFE), and tetra(ethylene glycol) diacrylateswere stirred evenly to form a solution. Bis trifluoromethyl sulfimidelithium was then dissolved in the solution to obtain a solution mixture.In this solution mixture, the weight fractions for the four ingredientswere VEC (40%). HFE (20%), tetra(ethylene glycol) diacrylates (20%), andbis trifluoromethyl sulfimide (10%).

The mixed solution was added to a lithium-ion cell having an NCMcathode, graphite anode, particles of ISE prepared in Example 1, andporous PE/PP membrane. After the mixed solution was injected, the mixedsolution accounted for 3% of the total cell weight. The cell was exposedto electron beam at 50° C. until a dosage of 20 kGy was reached. VEC waspolymerized and crosslinked to become a solid polymer, but HFE remainedas a liquid.

Example 9: Lithium-Ion Cell Featuring an In Situ Polymerized PhenylVinyl Sulfide (PVS) in the Presence of a Second Solvent TMS (PVS/TMSRatio=9/1)

TMS has the following chemical formula:

The lithium-ion cells prepared in this example comprise an anode ofmeso-carbon micro-beads (MCMB, an artificial graphite supplied fromChina Steel Chemical Co. Taiwan), a cathode of NCM-622 particles, and aporous PE/PP membrane as a separator.

Phenyl vinyl sulfide (first liquid solvent), TMS (second solvent). CTA(chain transfer agent, shown below), AIBN (initiator, 1.0%), and 5% byweight of lithium trifluoro-metasulfonate (LiCF₃SO₃), were mixed aninjected into the lithium-ion cell, and heated at 60° C. to obtain abattery cell containing an in situ cued polymer electrolyte mixed withparticles of an ISE obtained in Example 4.

Example 10: Lithium-Ion Cell Featuring an In Situ Polymerized PhenylVinyl Sulfone

The lithium-ion cells prepared in this example comprise an anode ofgraphene-protected Si particles, a cathode of NCM-622 particles,particles of an ISE prepared in Example 2, and a porous PE/PP membraneas a separator.

Phenyl vinyl sulfone (PVS) can be polymerized with several anionic-typeinitiators; e.g., n-BuLi, ZnEt2, LiN(CH₂)₂, and NaNH₂. The secondsolvent may be selected from pyridine, sulfolane, Trimethyl phosphate(TMP), Trifluoro-Phosphate (TFP), etc. Trimethyl phosphate has thefollowing chemical structure:

A mixture of PVS, TFP, n-BuLi (1.0% relative to PVS), and LiBF₄ (0.5 M)was thoroughly mixed and injected into the battery cell, which wasmaintained at 30° C. overnight to cure the polymer.

Example 11: Quasi-Solid and Solid-State Electrolytes fromVinylphosphonic Acid (VPA)

The free radical polymerization of vinylphosphonic acid (VPA) can becatalyzed with benzoyl peroxide as the initiator. In a procedure, 150parts vinylphosphonic acid, 0.75 parts benzoyl peroxide, and 20 parts oflithium bis(oxalato)borate (LiBOB) were dissolved in 150 partsisopropanol. For the preparation of lithium cells, dry cells wereinjected with the reactive mass, followed by removal of most of theisopropanol and replaced with TFP as a second solvent. The cell was thenheated for 5 hours at 90° C. to form polyvinylphosphonic acid, mixedwith 5% by weight TFP.

In a separate experiment, vinylphosphonic acid was heated to >45° C.(melting point of VPA=36° C.), which was added with benzoyl peroxide,LiBOB, and 25% by weight of a garnet-type solid electrolyte(Li₇La₃Zr₂O₁₂ (LLZO) powder). After rigorous stirring, the resultingpaste was cast onto a glass surface and cured at 90° C. for 5 hours toform a solid electrolyte separator to be disposed between an anode and acathode layer. For a lithium-ion cell, a natural graphite-based anode, asolid electrolyte separator, and a LiCoO₂-based cathode were combined.For an anode-less lithium cell, a solid electrolyte separator layer isimplemented between a Cu foil and a LiCoO₂-based cathode layer.

Electrochemical measurements (CV curves) were carried out in anelectrochemical workstation at a scanning rate of 1-100 mV/s. Theelectrochemical performance of the cells was evaluated by galvanostaticcharge/discharge cycling at a current density of 50-500 mA/g using anArbin electrochemical workstation. Testing results indicate that thecells containing quasi-solid or solid-state electrolytes obtained by insitu curing perform very well. These cells are flame resistant andrelatively safe.

Example 12: In Situ Cured Diethyl Vinylphosphonate and DiisopropylVinylphosphonate Polymer Electrolytes in a Lithium/NCM-532 Cell(Initially the Cell being Lithium-Free) and Lithium-Ion Cell Containinga Si-Based Anode and an NCM-532 Cathode

Both diethyl vinylphosphonate and diisopropyl vinylphosphonate can bepolymerized by a peroxide initiator (di-tert-butyl peroxide), along withLiBF₄, to clear, light-yellow polymers of low molecular weight. In atypical procedure, either 85% by weight of diethyl vinylphosphonate ordiisopropyl vinylphosphonate (being a liquid at room temperature) and 5%of a second liquid solvent (unsaturated phosphazene) were added withdi-tert-butyl peroxide (1% by weight) and LiBF₄ (9% by weight) to form areactive solution. The solution was heated to 45° C. and injected into adry battery cell. Bulk polymerization was allowed to proceed for 2-12hours inside a battery cell. For the construction of a lithium-ion cell,a graphene-coated Si particle-based anode, a porous separator, and aNCM-532-based cathode were stacked and housed in a plastic/Al laminatedenvelop to form a cell. For the construction of a lithium metal cell, aCu foil anode current collector, a porous separator, and a NCM-532-basedcathode were stacked and housed in a plastic/Al laminated envelop toform a cell.

Additionally, layers of diethyl vinylphosphonate and diisopropylvinylphosphonate polymer electrolytes were cast on glass surfaces andpolymerized under comparable conditions. The lithium ion conductivity ofthese solid-state electrolytes was measured. The lithium ionconductivity of diethyl vinylphosphonate derived polymers was found tobe in the range of 5.4×10⁻⁵ S/cm-7.3×10⁻⁴ S/cm and that of diisopropylvinylphosphonate polymer electrolytes in the range of 6.6×10⁻⁵S/cm-8.4×10⁻⁴ S/cm without a second solvent. Both arm solid stateelectrolytes that are highly flame resistant. The presence ofphosphazene liquid was found to increase the lithium ion conductivity by3-5 times.

In several samples, a garnet-type solid electrolyte (Li₇La₃Zr₂O₁₂ (LLZO)powder) was added into the cathode (NCM-532) in the anode-less lithiumbattery.

Example 13: Solid State Electrolytes Via In Situ Curing of Cyclic Estersof Phosphoric Acid

As selected examples of polymers from phosphates, five-membered cyclicesters of phosphoric acid of the general formula: —CH₂CH(R)OP(O)—(OR′)O—were polymerized to solid, soluble polymers of high molecular weight byusing n-C₄H₉Li, (C₅H₅)₂Mg, or (i-C₄H₉)₃Al as initiators. The resultingpolymers have a repeating unit as follows:

where R is H, with R′=CH₃, C₂H₅, n-C₃H₇, i-C₃H₇; n-C₄H₉, CCl₃CH₂, orC₆H₅, or R is CH₂Cl and R′ is C₂H₅. The polymers typically haveM_(n)=10⁴-10⁵.

In a representative procedure, initiators n-C₄H₉Li (0.5% by weight) and5% lithium bis(oxalato)borate (LiBOB) as a lithium salt were mixed with2-alkoxy-2-oxo-1,3,2-dioxaphospholan (R′=H in the following chemicalformula):

A second solvent, DMMP, having the following structure, was used toadjust the viscosity of the reactant mixture:

The mixture was introduced into a battery cell and the anionicpolymerization was allowed to proceed at room temperature (or lower)overnight to produce a solid state electrolyte in situ. The roomtemperature lithium ion conductivities of this series of solidelectrolytes are in the range of 2.5×10⁻⁵ S/cm-1.6×10⁻³ S/cm.

Both Li metal cells (containing a lithium foil as an anode material) andLi-ion cells (containing artificial graphite particles as an anodeactive material) were prepared. Both cells comprise NCA particles as thecathode active material.

1. A rechargeable lithium battery cell comprising an anode, a cathode,and a hybrid quasi-solid or solid-state electrolyte in ioniccommunication with the anode and the cathode, wherein: the hybridelectrolyte, having a lithium ion conductivity from 10⁻⁵ S/cm to 5×10⁻²S/cm, comprises a mixture of a polymer and an inorganic solidelectrolyte; the polymer is a polymerization or crosslinking product ofa reactive additive, wherein the reactive additive comprises (i) a firstliquid solvent that is polymerizable, (ii) an initiator or curing agent,and (iii) a lithium salt; wherein the first liquid solvent occupies from1% to 99% by weight based on the total weight of the reactive additive;the polymer is present in the anode, the cathode, the separator, aninterface between the anode and the separator, and/or an interfacebetween the cathode and the separator; and the hybrid electrolyte formsa contiguous phase in the cathode or in the anode, and occupies from 3%to 40% by volume of the cathode or from 3% to 40% by volume of theanode.
 2. The rechargeable lithium cell of claim 1, wherein theinorganic solid electrolyte material is selected from an oxide type,sulfide type, hydride type, halide type, borate type, phosphate type,lithium phosphorus oxynitride (LiPON), garnet-type, lithium superionicconductor (LISICON) type, sodium superionic conductor (NASICON) type, ora combination thereof.
 3. The rechargeable lithium cell of claim 1,wherein the first liquid solvent is selected from the group consistingof vinylene carbonate, ethylene carbonate, fluoroethylene carbonate,ethylene glycol phenyl ether acrylate) (PEGPEA), ethoxylated trimethylpropyl triacrylate (ETPTA), tetrahydrofuran (THF), vinyl sulfite, vinylethylene sulfite, vinyl ethylene carbonate, 1,3-propyl sultone,1,3,5-trioxane (TXE), 1,3-acrylic-sultones, methyl ethylene sulfone,methyl vinyl sulfone, ethyl vinyl sulfone, methyl methacrylate, vinylacetate, acrylamide, 1,3-dioxolane (DOL), fluorinated ethers,fluorinated esters, sulfones, sulfides, dinitriles, acrylonitrile (AN),sulfates, siloxanes, silanes, N-methylacetamide, acrylates, ethyleneglycols, phosphates, phosphonates, phosphinates, phosphines, phosphineoxides, phosphonic acids, phosphorous acid, phosphites, phosphoricacids, phosphazene compounds, derivatives thereof, and combinationsthereof.
 4. The rechargeable lithium cell of claim 1, wherein theelectrolyte further comprises a second liquid solvent occupying from0.1% to 30% by weight of the total electrolyte weight, wherein the firstliquid solvent has a lower flash point, a higher vapor pressure, or ahigher solubility of the lithium salt as compared with the second liquidsolvent.
 5. The rechargeable lithium cell of claim 4, wherein the secondliquid solvent comprises an ionic liquid selected from the groupconsisting of room temperature ionic liquids having a cation selectedfrom tetraalkylammonium, di-, tri-, or tetra-alkylimidazolium,alkylpyridinium, dialkyl-pyrrolidinium, dialkylpiperidinium,tetraalkylphosphonium, hexakis(bromomethyl)benzene, andtrialkylsulfonium, 1-vinyl-3-dodecyl imidazoliumbis(trifluoromethanesulfonyl) imide (VDIM-TFSI),1-vinyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide(VMIMTFSI), 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (EMITFSI), [(poly(diallyldimethyl ammoniumbis(fluorosulfonyl)imide, (C₁₀H₁₆F₂N₂O₄S₂)n, vinylimidazolium monomerswith N-alkyl substituents, and combinations thereof.
 6. The rechargeablelithium cell of claim 4, wherein the second liquid solvent comprises anionic liquid comprising an anion selected from BF₄ ⁻, B(CN)₄ ⁻, CH₃BF₃⁻, CH₂CHBF₃ ⁻, CF₃BF₃ ⁻, C₂F₅BF₃ ⁻, n-C₃F₇BF₃ ⁻, n-C₄F₉BF₃ ⁻, PF₆ ⁻,CF₃CO₂ ⁻, CF₃SO₃ ⁻, N(SO₂CF₃)₂ ⁻, N(COCF₃)(SO₂CF₃)⁻, N(SO₂F)₂ ⁻, N(CN)₂⁻, C(CN)₃ ⁻, SCN⁻, SeCN⁻, CuCl₂ ⁻, AlCl₄ ⁻, F(HF)_(2.3) ⁻, or acombination thereof.
 7. The rechargeable lithium cell of claim 4,wherein the second liquid solvent, different in chemical compositionthan the first liquid solvent, comprises a liquid selected from thegroup consisting of fluorinated ethers, fluorinated esters, sulfones,sulfides, nitriles, sulfates, siloxanes, silanes, phosphates,phosphonates, phosphinates, phosphines, phosphine oxides, phosphonicacids, phosphorous acid, phosphites, phosphoric acids, phosphazenecompounds, derivatives thereof, and combinations thereof.
 8. Therechargeable lithium cell of claim 1, wherein the electrolyte furthercomprises a flame retardant selected from an organic phosphoruscompound, an inorganic phosphorus compound, a halogenated derivativethereof, or a combination thereof.
 9. The rechargeable lithium cell ofclaim 4, wherein the second liquid solvent further comprises a liquidselected from a phosphate, phosphonate, phosphinate, phosphine, orphosphine oxide having the structure of:

wherein R¹⁰, R¹¹, and R¹², are independently selected from the groupconsisting of alkyl, aryl, heteroalkyl, heteroaryl, halogen substitutedalkyl, halogen substituted aryl, halogen substituted heteroalkyl,halogen substituted heteroaryl, alkoxy, aryloxy, heteroalkoxy,heteroaryloxy, halogen substituted alkoxy, halogen substituted aryloxy,halogen substituted heteroalkoxy, and halogen substituted heteroaryloxyfunctional groups, and the second liquid solvent is stable under anapplied electrical potential no less than 4 V.
 10. The rechargeablelithium cell of claim 4, wherein the first or the second liquid solventcomprises a phosphoranamine having the structure of:

wherein R¹, R², and R³ are independently selected from the groupconsisting of alkyl, aryl, heteroalkyl, heteroaryl, halogen substitutedalkyl, halogen substituted aryl, halogen substituted heteroalkyl,halogen substituted heteroaryl, alkoxy, aryloxy, heteroalkoxy,heteroaryloxy, halogen substituted alkoxy, halogen substituted aryloxy,halogen substituted heteroalkoxy, and halogen substituted heteroaryloxyfunctional groups, wherein R¹, R², and R³ are represented by at leasttwo different substituents and wherein X is selected from the groupconsisting of an organosiylyl group or a tert-butyl group.
 11. Therechargeable lithium cell of claim 10, wherein R¹, R², and R³ are eachindependently selected from the group consisting of an alkoxy group, andan aryloxy group.
 12. The rechargeable lithium cell of claim 1, whereinthe lithium salt occupies 0.1%-30% by weight and the crosslinking agentand/or the initiator occupies 0.1-50% by weight of the reactiveadditive.
 13. The rechargeable lithium cell of claim 1, wherein thefirst liquid solvent comprises a solvent selected from the groupconsisting of fluorinated vinyl carbonates, fluorinated vinyl monomers,fluorinated esters, fluorinated vinyl esters, and fluorinated vinylethers and combinations thereof.
 14. The rechargeable lithium cell ofclaim 1, wherein the first liquid solvent comprises a sulfone or sulfideselected from vinyl sulfone, allyl sulfone, alkyl vinyl sulfone, arylvinyl sulfone, vinyl sulfide, TrMS, MTrMS, TMS, EMS, MMES, EMES, EMEES,or a combination thereof:


15. The rechargeable lithium cell of claim 14, wherein the vinyl sulfoneor sulfide is selected from ethyl vinyl sulfide, allyl methyl sulfide,phenyl vinyl sulfide, phenyl vinyl sulfoxide, allyl phenyl sulfone,allyl methyl sulfone, divinyl sulfone, or a combination thereof, whereinthe vinyl sulfone does not include methyl ethylene sulfone and ethylvinyl sulfone.
 16. The rechargeable lithium cell of claim 1, wherein thefirst liquid solvent comprises a nitrile, a dinitrile selected from ADN,GLN, or SEN, or a combination thereof:


17. The rechargeable lithium cell of claim 1, wherein the first liquidsolvent comprises a phosphate selected from allyl-type, vinyl-type,styrenic-type and (meth)acrylic-type monomers bearing a phosphonatemoiety.
 18. The rechargeable lithium cell of claim 1, wherein the firstliquid solvent comprises a phosphate, phosphonate, phosphonic acid,phosphazene, or phosphite selected from TMP, TEP, TFP, TDP, DPOF, DMMP,DMMEMP, tris(trimethylsilyl)phosphite (TTSPi), alkyl phosphate, triallylphosphate (TAP), or a combination thereof, wherein TMP, TEP, TFP, TDP,DPOF, DMMP, DMMEMP, and phosphazene have the following chemicalformulae:

wherein R=H, NH₂, or C₁-C₆ alkyl.
 19. The rechargeable lithium cell ofclaim 1, wherein the first liquid solvent comprises siloxane or silaneselected from alkylsiloxane (Si—O), alkyylsilane (Si—C), liquidoligomeric silaxane (—Si—O—Si—), or a combination thereof.
 20. Therechargeable lithium cell of claim 1, wherein the reactive additivefurther comprises an amide group selected from N,N-dimethylacetamide,N,N-diethylacetamide, N,N-dimethylformamide, N,N-diethylformamide, or acombination thereof.
 21. The rechargeable lithium cell of claim 1,wherein the crosslinking agent comprises a compound having at least onereactive group selected from a hydroxyl group, an amino group, an iminogroup, an amide group, an acrylic amide group, an amine group, anacrylic group, an acrylic ester group, or a mercapto group in themolecule.
 22. The rechargeable lithium cell of claim 1, wherein thecrosslinking agent is selected from poly(diethanol) diacrylate,poly(ethyleneglycol)dimethacrylate, poly(diethanol) dimethylacrylate,poly(ethylene glycol) diacrylate, or a combination thereof.
 23. Therechargeable lithium cell of claim 1, wherein said initiator is selectedfrom an azo compound, azobisisobutyronitrile, azobisisoheptonitrile,dimethyl azobisisobutyrate, benzoyl peroxide tert-butyl peroxide andmethyl ethyl ketone peroxide, benzoyl peroxide (BPO),bis(4-tert-butylcyclohexyl)peroxydicarbonate, t-amyl peroxypivalate,2,2′-azobis-(2,4-dimethylvaleronitrile),2,2′-azobis-(2-methylbutyronitrile),1,1-azobis(cyclohexane-1-carbonitrile, benzoylperoxide (BPO), hydrogenperoxide, dodecamoyl peroxide, isobutyryl peroxide, cumenehydroperoxide, tert-butyl peroxypivalate, diisopropyl peroxydicarbonate,lithium hexafluorophosphate (LiPF₆), lithium borofluoride (LiBF₄),lithium hexafluoroarsenide (LiAsF₆), lithium trifluoro-metasulfonate(LiCF₃SO₃), bis-trifluoromethyl sulfonylimide lithium (LiN(CF₃SO₂)₂),lithium bis(oxalato)borate (LiBOB), lithium oxalyldifluoroborate(LiBF₂C₂O₄), lithium oxalyldifluoroborate (LiBF₂C₂O₄), or a combinationthereof.
 24. The rechargeable lithium cell of claim 1, wherein saidlithium salt is selected from lithium perchlorate (LiClO₄), lithiumhexafluorophosphate (LiPF₆), lithium borofluoride (LiBF₄), lithiumhexafluoroarsenide (LiAsF₆), lithium trifluoro-metasulfonate (LiCF₃SO₃),bis-trifluoromethyl sulfonylimide lithium (LiN(CF₃SO₂)₂), lithiumbis(oxalato)borate (LiBOB), lithium oxalyldifluoroborate (LiBF₂C₂O₄),lithium oxalyldifluoroborate (LiBF₂C₂O₄), lithium nitrate (LiNO₃),Li-Fluoroalkyl-Phosphates (LiPF₃(CF₂CF₃)₃), lithiumbisperfluoro-ethysulfonylimide (LiBETI), lithiumbis(trifluoromethanesulphonyl)imide, lithium bis(fluorosulphonyl)imide,lithium trifluoromethanesulfonimide (LiTFSI), an ionic liquid lithiumsalt, or a combination thereof.
 25. The rechargeable lithium cell ofclaim 1, wherein the cathode comprises a cathode active materialselected from lithium nickel manganese oxide (LiNi_(a)Mn_(2−a)O₄,0<a<2), lithium nickel manganese cobalt oxide(LiNi_(n)Mn_(m)Co_(1−n−m)O₂, 0<n<1, 0<m<1, n+m<1), lithium nickel cobaltaluminum oxide (LiNi_(c)Co_(d)A_(1−c−d)O₂, 0<c<1, 0<d<1, c+d<1), lithiummanganate (LiMn₂O₄), lithium iron phosphate (LiFePO₄), lithium manganeseoxide (LiMnO₂), lithium cobalt oxide (LiCoO₂), lithium nickel cobaltoxide (LiNi_(p)Co_(1−p)O₂, 0<p<1), or lithium nickel manganese oxide(LiNi_(q)Mn_(2−q)O₄, 0<q<2).
 26. The rechargeable lithium cell of claim1, which is a lithium-ion cell wherein the anode comprises an anodeactive material selected from the group consisting of: (a) silicon (Si),germanium (Ge), tin (Sn), lead (Pb), antimony (Sb), phosphorus (P),bismuth (Bi), zinc (Zn), aluminum (Al), titanium (Ti), nickel (Ni),cobalt (Co), and cadmium (Cd); (b) alloys or intermetallic compounds ofSi, Ge, Sn, Pb, Sb, Bi, Zn, Al, Ti, Ni, Co, or Cd with other elements;(c) oxides, carbides, nitrides, sulfides, phosphides, selenides, andtellurides of Si, Ge, Sn, Pb, Sb, Bi, Zn, Al, Ti, Fe, Ni, Co, V, or Cd,and their mixtures, composites, or lithium-containing composites; (d)salts and hydroxides of Sn; (e) lithium titanate, lithium manganate,lithium aluminate, lithium titanium niobate, lithium-containing titaniumoxide, lithium transition metal oxide, ZnCo₂O₄; (f) carbon or graphiteparticles (g) prelithiated versions thereof; and (h) combinationsthereof.
 27. The rechargeable lithium cell of claim 1, which is alithium metal secondary cell, a lithium-ion cell, a lithium-sulfur cell,a lithium-ion sulfur cell, a lithium-selenium cell, or a lithium-aircell.
 28. The rechargeable lithium cell of claim 1, further comprising aseparator disposed between the anode and the cathode wherein theseparator comprises the hybrid quasi-solid or solid-state electrolyte.29. A process for producing the rechargeable lithium cell, the processcomprising: a) Preparing a cathode comprising particles of a cathodeactive material, particles of an inorganic solid electrolyte, and aconducting filler; b) Preparing an anode; c) Preparing a reactiveelectrolyte composition comprising (i) a first liquid solvent that ispolymerizable, (ii) an initiator or curing agent, and (iii) a lithiumsalt, wherein the first liquid solvent occupies from 1% to 99% by weightbased on the total weight of the reactive electrolyte composition; d)Combining the cathode, the anode, and a separator layer to form a cell;and e) Introducing the reactive electrolyte composition into thecathode, the anode, the separator, or the cell, followed by polymerizingand/or crosslinking the reactive electrolyte composition to form therechargeable lithium cell.
 30. The process of claim 29, wherein step (d)is conducted before or after step (e).
 31. The process of claim 29,wherein step (b) comprises a procedure of mixing an anode activematerial, an inorganic solid electrolyte, and a conducting filler toform the anode.
 32. The process of claim 29, wherein the inorganic solidelectrolyte material is selected from an oxide type, sulfide type,hydride type, halide type, borate type, phosphate type, lithiumphosphorus oxynitride (LiPON), garnet-type, lithium superionic conductor(LISICON) type, sodium superionic conductor (NASICON) type, or acombination thereof.
 33. The process of claim 29, wherein the firstliquid solvent comprises a liquid selected from the group consisting ofvinylene carbonate, ethylene carbonate, fluoroethylene carbonate,ethylene glycol phenyl ether acrylate) (PEGPEA), ethoxylated trimethylpropyl triacrylate (ETPTA), tetrahydrofuran (THF), vinyl sulfite, vinylethylene sulfite, vinyl ethylene carbonate, 1,3-propyl sultone,1,3,5-trioxane (TXE), 1,3-acrylic-sultones, methyl ethylene sulfone,methyl vinyl sulfone, ethyl vinyl sulfone, methyl methacrylate, vinylacetate, acrylamide, 1,3-dioxolane (DOL), fluorinated ethers,fluorinated esters, sulfones, sulfides, dinitriles, acrylonitrile (AN),sulfates, siloxanes, silanes, N-methylacetamide, acrylates, ethyleneglycols, phosphates, phosphonates, phosphinates, phosphines, phosphineoxides, phosphonic acids, phosphorous acid, phosphites, phosphoricacids, phosphazene compounds, derivatives thereof, and combinationsthereof.
 34. The process of claim 29, wherein the first liquid solventcomprises a solvent selected from the group consisting of fluorinatedethers, fluorinated esters, sulfones, sulfides, nitriles, sulfates,siloxanes, silanes, combinations thereof, and combinations withphosphates, phosphonates, phosphinates, phosphines, phosphine oxides,phosphonic acids, phosphorous acid, phosphites, phosphoric acids,phosphazene compounds, derivatives thereof, and combinations thereof.35. The process of claim 29, wherein the separator layer comprises aninorganic solid electrolyte material.
 36. The process of claim 29,wherein the cathode further includes a resin binder.
 37. The process ofclaim 31, wherein the anode further includes a resin binder.